A212124 -id:A212124 - cp's OEIS frontend

A212121 Triangle read by rows in which row n lists the number of pairs of states of the subshells of the n-th shell of the nuclear shell model ordered by energy level in increasing order.

1, 2, 1, 3, 1, 2, 4, 2, 3, 1, 5, 4, 3, 2, 1, 6, 5, 4, 3, 2, 1, 7, 5, 3, 6, 4, 1, 2, 8

Offset: 1

Omar E. Pol, Jun 03 2012

For another version see A213361. First differs from A213361 at a(12).

What defines this sequence? (This appears to be some sort of permutation of A130517 by shifting columns down or upwards in some randomized way.) - R. J. Mathar, Jul 22 2012

			Illustration of initial terms: two views of a three-dimensional shell model of nucleus.
.
.|-------------------------- j --------------------------|
.|                                                       |
.|   |---------------------- i ----------------------|   |
.|   |                                               |   |
.|   |   |------------------ h ------------------|   |   |
.|   |   |                                       |   |   |
.|   |   |   |-------------- g --------------|   |   |   |
.|   |   |   |                               |   |   |   |
.|   |   |   |   |---------- f ----------|   |   |   |   |
.|   |   |   |   |                       |   |   |   |   |
.|   |   |   |   |   |------ d ------|   |   |   |   |   |
.|   |   |   |   |   |               |   |   |   |   |   |
.|   |   |   |   |   |   |-- p --|   |   |   |   |   |   |
.|   |   |   |   |   |   |       |   |   |   |   |   |   |
.|   |   |   |   |   |   |   s   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   2   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   1   |   |   |   |   |   |
.|   |   |   |   |   3   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   2   |   |   |   |   |
.|   |   |   |   4   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   2   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   3   |   |   |   |
.|   |   |   |   |   |   |   |   1   |   |   |   |   |   |
.|   |   |   5   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   4   |   |   |
.|   |   |   |   |   3   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   2   |   |   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   6   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   5   |   |
.|   |   |   |   4   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   3   |   |   |   |
.|   |   |   |   |   |   2   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   1   |   |   |   |   |   |
.|   7   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   5   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   3   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   6   |
.|   |   |   |   |   |   |   |   |   |   |   4   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   2   |   |   |   |   |
.8   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |1/2|   |   |   |   |   |   |
.|   |   |   |   |   |   |           |   |   |   |   |   |
.|   |   |   |   |   |   |----3/2----|   |   |   |   |   |
.|   |   |   |   |   |                   |   |   |   |   |
.|   |   |   |   |   |--------5/2--------|   |   |   |   |
.|   |   |   |   |                           |   |   |   |
.|   |   |   |   |------------7/2------------|   |   |   |
.|   |   |   |                                   |   |   |
.|   |   |   |----------------9/2----------------    |   |
.|   |   |                                           |   |
.|   |   |-------------------11/2--------------------|   |
.|   |                                                   |
.|   |-----------------------13/2------------------------|
.|
.|---------------------------15/2-------------------------
.
..........................................................
.
.|-------------------------- j --------------------------|
.|                                                       |
.*   |---------------------- i ----------------------|   |
.|   |                                               |   |
.|   *   |------------------ h ------------------|   |   *
.|   |   |                                       |   |   |
.*   |   *   |-------------- f --------------|   |   *   |
.|   |   |   |                               |   |   |   |
.|   *   |   *   |---------- e ----------|   |   *   |   *
.|   |   |   |   |                       |   |   |   |   |
.*   |   *   |   *   |------ d ------|   |   *   |   *   |
.|   |   |   |   |   |               |   |   |   |   |   |
.|   *   |   *   |   *   |-- p --|   |   *   |   *   |   *
.|   |   |   |   |   |   |       |   |   |   |   |   |   |
.*   |   *   |   *   |   *   s   |   *   |   *   |   *   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   *   |   *   |   *   |   *   *   |   *   |   *   |   *
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.*   |   *   |   *   |   *   |1/2|   *   |   *   |   *   |
.|   |   |   |   |   |   |           |   |   |   |   |   |
.|   *   |   *   |   *   |----3/2----|   *   |   *   |   *
.|   |   |   |   |   |                   |   |   |   |   |
.*   |   *   |   *   |--------5/2--------|   *   |   *   |
.|   |   |   |   |                           |   |   |   |
.|   *   |   *   |------------7/2------------|   *   |   *
.|   |   |   |                                   |   |   |
.*   |   *   |----------------9/2----------------|   *   |
.|   |   |                                           |   |
.|   *   |-------------------11/2--------------------|   *
.|   |                                                   |
.*   |-----------------------13/2------------------------|
.|
.|---------------------------15/2-------------------------
.
Written as an irregular triangle in which row n represents the n-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
1;
2, 1;
3, 1, 2;
4;
2, 3, 1, 5;
4, 3, 2, 1, 6;
5, 4, 3, 2, 1, 7;
5, 3, 6, 4, 1, 2, 8;
...

Partial sums give A212123.

Cf. A018226, A130517, A212122, A212124, A213361-A213364.

a(n) = A212122(n)/2.

A213364 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

2, 6, 8, 14, 16, 20, 28, 32, 38, 40, 50, 56, 64, 66, 70, 82, 90, 94, 108, 118, 120, 126, 136, 148, 164, 170, 172, 180, 184

Offset: 1

Omar E. Pol, Jun 23 2012

First differs from A212124 at a(12).

			Written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
2;
6,     8;
14,   16,  20;
28;
32,   38,  40,  50;
56,   64,  66,  70,  82;
90,   94, 108, 118, 120, 126;
136, 148, 164, 170, 172, 180, 184;
...
First seven terms of right border give the "magic numbers" A018226

I. Talmi, Simple Models of Complex Nuclei, Hardwood Academic Publishers (1993).

Partial sums of A213362. Other versions are A210984, A212014, A212124, A213374.

Cf. A018226, A212121-A212124, A213361, A213363.

a(n) = 2*A213363(n).

A212122 Triangle read by rows in which row n lists the number of states of the subshells of the n-th shell of the nuclear shell model ordered by energy level in increasing order.

Original entry on oeis.org

2, 4, 2, 6, 2, 4, 8, 4, 6, 2, 10, 8, 6, 4, 2, 12, 10, 8, 6, 4, 2, 14, 10, 6, 12, 8, 2, 4, 16

Offset: 1

Omar E. Pol, Jun 03 2012

First differs from A213362 at a(12).

The list of the spin-orbit coupling of this version of the nuclear shell model starts: 1s_(1/2), 1p_(3/2), 1p_(1/2), 1d_(5/2), 2s_(1/2), 1d_(3/2), 1f_(7/2), 2p_(3/2), 1f_(5/2), 2p_(1/2), 1g_(9/2), 1g_(7/2), 2d_(5/2), 2d_(3/2), etc. (see link section). The numerators of the fractions are 1, 3, 1, 5, 1, 3, 7, 3, 5, 1, 9, 7, 5, 3,... then we add 1 to every numerator, so we have this sequence: 2, 4, 2, 6, 2, 4, 8, 4, 6, 2, 10, 8, 6, 4,... Other sequences that arise from this sequence are A212121, A212123, A212124. - Omar E. Pol, Sep 02 2012

			Illustration of initial terms: two views of a three-dimensional shell model of nucleus.
|-------------------------- j --------------------------|
|                                                       |
|   |---------------------- i ----------------------|   |
|   |                                               |   |
|   |   |------------------ h ------------------|   |   |
|   |   |                                       |   |   |
|   |   |   |-------------- g --------------|   |   |   |
|   |   |   |                               |   |   |   |
|   |   |   |   |---------- f ----------|   |   |   |   |
|   |   |   |   |                       |   |   |   |   |
|   |   |   |   |   |------ d ------|   |   |   |   |   |
|   |   |   |   |   |               |   |   |   |   |   |
|   |   |   |   |   |   |-- p --|   |   |   |   |   |   |
|   |   |   |   |   |   |       |   |   |   |   |   |   |
|   |   |   |   |   |   |   s   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   2   |   |   |   |   |   |   |
|   |   |   |   |   |   4   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   2   |   |   |   |   |   |
|   |   |   |   |   6   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   2   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   4   |   |   |   |   |
|   |   |   |   8   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   4   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   6   |   |   |   |
|   |   |   |   |   |   |   |   2   |   |   |   |   |   |
|   |   |  10   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   8   |   |   |
|   |   |   |   |   6   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   4   |   |   |   |   |
|   |   |   |   |   |   |   2   |   |   |   |   |   |   |
|   |  12   |   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |  10   |   |
|   |   |   |   8   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   6   |   |   |   |
|   |   |   |   |   |   4   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   2   |   |   |   |   |   |
|  14   |   |   |   |   |   |   |   |   |   |   |   |   |
|   |   |  10   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   6   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |   |  12   |
|   |   |   |   |   |   |   |   |   |   |   8   |   |   |
|   |   |   |   |   |   |   2   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   4   |   |   |   |   |
16  |   |   |   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
|   |   |   |   |   |   |   |1/2|   |   |   |   |   |   |
|   |   |   |   |   |   |           |   |   |   |   |   |
|   |   |   |   |   |   |----3/2----|   |   |   |   |   |
|   |   |   |   |   |                   |   |   |   |   |
|   |   |   |   |   |--------5/2--------|   |   |   |   |
|   |   |   |   |                           |   |   |   |
|   |   |   |   |------------7/2------------|   |   |   |
|   |   |   |                                   |   |   |
|   |   |   |----------------9/2----------------|   |   |
|   |   |                                           |   |
|   |   |-------------------11/2--------------------|   |
|   |                                                   |
|   |-----------------------13/2------------------------|
|
|---------------------------15/2-------------------------
.
..........................................................
.
|-------------------------- j --------------------------|
*                                                       |
*   |---------------------- i ----------------------|   |
|   *                                               |   *
|   *   |------------------ h ------------------|   |   *
*   |   *                                       |   *   |
*   |   *   |-------------- f --------------|   |   *   |
|   *   |   *                               |   *   |   *
|   *   |   *   |---------- e ----------|   |   *   |   *
*   |   *   |   *                       |   *   |   *   |
*   |   *   |   *   |------ d ------|   |   *   |   *   |
|   *   |   *   |   *               |   *   |   *   |   *
|   *   |   *   |   *   |-- p --|   |   *   |   *   |   *
*   |   *   |   *   |   *       |   *   |   *   |   *   |
*   |   *   |   *   |   *   s   |   *   |   *   |   *   |
|   *   |   *   |   *   |   *   *   |   *   |   *   |   *
|   *   |   *   |   *   |   *   *   |   *   |   *   |   *
*   |   *   |   *   |   *   |   |   *   |   *   |   *   |
*   |   *   |   *   |   *   |1/2|   *   |   *   |   *   |
|   *   |   *   |   *   |           |   *   |   *   |   *
|   *   |   *   |   *   |----3/2----|   *   |   *   |   *
*   |   *   |   *   |                   |   *   |   *   |
*   |   *   |   *   |--------5/2--------|   *   |   *   |
|   *   |   *   |                           |   *   |   *
|   *   |   *   |------------7/2------------|   *   |   *
*   |   *   |                                   |   *   |
*   |   *   |----------------9/2----------------|   *   |
|   *   |                                           |   *
|   *   |-------------------11/2--------------------|   *
*   |                                                   |
*   |-----------------------13/2------------------------|
|
|---------------------------15/2-------------------------
.
Written as an irregular triangle in which row n represents the n-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
2;
4,   2;
6,   2,  4;
8;
4,   6,  2, 10;
8,   6,  4,  2, 12;
10,  8,  6,  4,  2, 14;
10,  6, 12,  8,  2,  4, 16;
...

M. Goeppert Mayer and J. Hans D. Jensen, Elementary Theory of Nuclear Shell Structure, J. Wiley and Sons, Inc. (1955).

HyperPhysics, G.S.U., Shell Model of Nucleus
Library of Halexandria, Nuclear shell model, Table 1.

Row sums give A210842. Partial sums give A212124.
Other versions are A162630, A212012, A213362, A213372.
Cf. A018226, A002378, A130517, A130598, A210842, A212121, A212123.

a(n) = 2*A212121(n).

A212014 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

2, 6, 8, 14, 18, 20, 28, 34, 38, 40, 50, 58, 64, 68, 70, 82, 92, 100, 106, 110, 112, 126, 138, 148, 156, 162, 166, 168, 184, 198, 210, 220, 228, 234, 238, 240, 258, 274, 288, 300, 310, 318, 324, 328, 330, 350, 368, 384, 398, 410, 420, 428, 434, 438, 440, 462, 482, 500, 516, 530, 542, 552, 560, 566, 570, 572

Offset: 1

Omar E. Pol, Jul 15 2012

			Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus. Triangle begins:
    2;
    6,   8;
   14,  18,  20;
   28,  34,  38,  40;
   50,  58,  64,  68,  70;
   82,  92, 100, 106, 110, 112;
  126, 138, 148, 156, 162, 166, 168;
  ...
Column 1 gives positive terms of A033547. Right border gives positive terms of A007290.
Example 2: written as an irregular triangle in which row j is related to the j-th shell of nucleus. In this case note that row 4 has only one term. Triangle begins:
    2;
    6,   8;
   14,  18,  20;
   28;
   34,  38,  40,  50;
   58,  64,  68,  70,  82;
   92, 100, 106, 110, 112, 126;
  138, 148, 156, 162, 166, 168, 184;
  ...
First seven terms of right border give the "magic numbers" A018226.

M. Goeppert Mayer, Nuclear configurations in the spin-orbit coupling model. I. Empirical evidence, Phys. Rev. 78: 16 (1950). II. Theoretical considerations, Phys. Rev. 78: 22 (1950).

Paolo Xausa, Table of n, a(n) for n = 1..11325 (rows 1..150 of triangle, flattened).

Partial sums of A212012. Other versions are A210984, A212124, A213364, A213374.

Cf. A004736, A007290, A033547, A018226, A212013.

2*Accumulate[Flatten[Range[Range[15], 1, -1]]] (* Paolo Xausa, Mar 14 2025 *)

a(n) = 2*A212013(n).

A212123 Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

1, 3, 4, 7, 8, 10, 14, 16, 19, 20, 25, 29, 32, 34, 35, 41, 46, 50, 53, 55, 56, 63, 68, 71, 77, 81, 82, 84, 92

Offset: 1

Omar E. Pol, Jun 03 2012

First differs from A213363 at a(12).

			Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus. Triangle begins:
1;
3,    4;
7,    8,  10;
14,  16,  19,  20;
25,  29,  32,  34,  35;
41,  46,  50,  53,  55,  56;
63,  68,  71,  77,  81,  82,  84;
...
Example 2: written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that in this case row 4 has only one term. Triangle begins:
1;
3,   4;
7,   8, 10;
14,
16, 19, 20, 25;
29, 32, 34, 35, 41;
46, 50, 53, 55, 56, 63;
68, 71, 77, 81, 82, 84, 92;
...

Partial sums of A212121. Other versions are A210983, A212013, A213363, A213373.

Cf. A000292, A004006, A212122, A212124.

a(n) = A212124(n)/2.

A213361 Triangle read by rows in which row n lists the number of pairs of states of the subshells of the n-th shell of the nuclear shell model ordered by energy level in increasing order.

Original entry on oeis.org

1, 2, 1, 3, 1, 2, 4, 2, 3, 1, 5, 3, 4, 1, 2, 6, 4, 2, 7, 5, 1, 3, 5, 6, 8, 3, 1, 4, 2

Offset: 1

Omar E. Pol, Jun 23 2012

For another version see A212121. First differs from A212121 at a(12).

			Illustration of initial terms: two views of a three-dimensional shell model of nucleus.
.
.|-------------------------- j --------------------------|
.|                                                       |
.|   |---------------------- i ----------------------|   |
.|   |                                               |   |
.|   |   |------------------ h ------------------|   |   |
.|   |   |                                       |   |   |
.|   |   |   |-------------- g --------------|   |   |   |
.|   |   |   |                               |   |   |   |
.|   |   |   |   |---------- f ----------|   |   |   |   |
.|   |   |   |   |                       |   |   |   |   |
.|   |   |   |   |   |------ d ------|   |   |   |   |   |
.|   |   |   |   |   |               |   |   |   |   |   |
.|   |   |   |   |   |   |-- p --|   |   |   |   |   |   |
.|   |   |   |   |   |   |       |   |   |   |   |   |   |
.|   |   |   |   |   |   |   s   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   2   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   1   |   |   |   |   |   |
.|   |   |   |   |   3   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   2   |   |   |   |   |
.|   |   |   |   4   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   2   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   3   |   |   |   |
.|   |   |   |   |   |   |   |   1   |   |   |   |   |   |
.|   |   |   5   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   3   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   4   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   2   |   |   |   |   |
.|   |   6   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   4   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   2   |   |   |   |   |   |   |   |
.|   7   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   5   |   |
.|   |   |   |   |   |   |   |   1   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   3   |   |   |   |
.|   |   |   5   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   6   |
.8   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   3   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   1   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   4   |   |   |
.|   |   |   |   |   |   |   |   |   2   |   |   |   |   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   |   |   |   |   |   |   |1/2|   |   |   |   |   |   |
.|   |   |   |   |   |   |           |   |   |   |   |   |
.|   |   |   |   |   |   |----3/2----|   |   |   |   |   |
.|   |   |   |   |   |                   |   |   |   |   |
.|   |   |   |   |   |--------5/2--------|   |   |   |   |
.|   |   |   |   |                           |   |   |   |
.|   |   |   |   |------------7/2------------|   |   |   |
.|   |   |   |                                   |   |   |
.|   |   |   |----------------9/2----------------|   |   |
.|   |   |                                           |   |
.|   |   |-------------------11/2--------------------|   |
.|   |                                                   |
.|   |-----------------------13/2------------------------|
.|
.|---------------------------15/2-------------------------
.
..........................................................
.
.|-------------------------- j --------------------------|
.|                                                       |
.*   |---------------------- i ----------------------|   |
.|   |                                               |   |
.|   *   |------------------ h ------------------|   |   *
.|   |   |                                       |   |   |
.*   |   *   |-------------- f --------------|   |   *   |
.|   |   |   |                               |   |   |   |
.|   *   |   *   |---------- e ----------|   |   *   |   *
.|   |   |   |   |                       |   |   |   |   |
.*   |   *   |   *   |------ d ------|   |   *   |   *   |
.|   |   |   |   |   |               |   |   |   |   |   |
.|   *   |   *   |   *   |-- p --|   |   *   |   *   |   *
.|   |   |   |   |   |   |       |   |   |   |   |   |   |
.*   |   *   |   *   |   *   s   |   *   |   *   |   *   |
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.|   *   |   *   |   *   |   *   *   |   *   |   *   |   *
.|   |   |   |   |   |   |   |   |   |   |   |   |   |   |
.*   |   *   |   *   |   *   |1/2|   *   |   *   |   *   |
.|   |   |   |   |   |   |           |   |   |   |   |   |
.|   *   |   *   |   *   |----3/2----|   *   |   *   |   *
.|   |   |   |   |   |                   |   |   |   |   |
.*   |   *   |   *   |--------5/2--------|   *   |   *   |
.|   |   |   |   |                           |   |   |   |
.|   *   |   *   |------------7/2------------|   *   |   *
.|   |   |   |                                   |   |   |
.*   |   *   |----------------9/2----------------|   *   |
.|   |   |                                           |   |
.|   *   |-------------------11/2--------------------|   *
.|   |                                                   |
.*   |-----------------------13/2------------------------|
.|
.|---------------------------15/2-------------------------
.
Written as an irregular triangle in which row n represents the n-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
1;
2, 1;
3, 1, 2;
4;
2, 3, 1, 5;
3, 4, 1, 2, 6;
4, 2, 7, 5, 1, 3;
5, 6, 8, 3, 1, 4, 2;

Partial sums give A213363.

Cf. A018226, A130517, A212121-A212124, A213362, A213364.

a(n) = A213362(n)/2.

A213374 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

2, 6, 8, 14, 16, 20, 28, 32, 38, 40, 50, 58, 64, 76, 80, 82, 90, 100, 114, 118, 124, 126

Offset: 1

Omar E. Pol, Jul 16 2012

First differs from A212124 at a(14). For more information see A213372.

			Written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
2;
6,    8;
14,  16,  20;
28;
32,  38,  40,  50;
58,  64,  76,  80,  82;
90, 100, 114, 118, 124, 126;
...
First seven terms of right border give the "magic numbers" A018226.

MIT OpenCourseWare, Energy Levels of Nucleons in a Smoothly-Varying Potential Well

Partial sums of A213372. Other versions are A210984, A212014, A212124, A213364.

Cf. A018226, A213371, A213373.

a(n) = 2*A213373(n).

A210983 Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

1, 3, 4, 7, 8, 10, 14, 16, 17, 20, 25, 28, 29, 31, 35, 41, 45, 47, 48, 51, 56, 63, 68, 71, 72, 74, 78, 84, 92, 98, 102, 104, 105, 108, 113, 120, 129, 136, 141, 144, 145, 147, 151, 157, 165, 175, 183, 189, 193, 195, 196, 199, 204, 211, 220, 231

Offset: 1

Omar E. Pol, Jul 14 2012

Additional comments from Omar E. Pol, Sep 02 2012: (Start)
Q: What are energy levels?
A: See the link sections of A212122, A213362, A213372. For example, see this link related to A213372: http://www.flickr.com/photos/mitopencourseware/3772864128/in/set-72157621892931990
Q: What defines the order in A212121?
A: The order of A212121 is defined by A212122.
Note that there are at least five versions of the nuclear shell model in the OEIS:
Goeppert-Mayer (1950): A212012, A004736, A212013, A212014.
Goeppert-Mayer, Jensen (1955): A212122, A212121, A212123, A212124.
Talmi (1993): A213362, A213361, A213363, A213364.
Meyerhof: A213372, A213371, A213373, A213374.
For another version: A162630, A130517, A210983, A210984.
Each version is represented by four sequences: the first sequence is the main entry.
(End)
For additional information see A162630.

			Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus, the sequence begins:
1;
3,     4;
7,     8,  10;
14,   16,  17,  20;
25,   28,  29,  31,  35;
41,   45,  47,  48,  51,  56;
63,   68,  71,  72,  74,  78,  84;
92,   98, 102, 104, 105, 108, 113, 120;
129, 136, 141, 144, 145, 147, 151, 157, 165;
175, 183, 189, 193, 195, 196, 199, 204, 211, 220;
...
Column 1 gives positive terms of A004006. Right border gives positives terms of A000292.
Example 2: written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that in this case row 4 has only one term. Triangle begins:
1;
3,     4;
7,     8,  10;
14;
16,   17,  20,  25;
28,   29,  31,  35,  41;
45,   47,  48,  51,  56,  63;
68,   71,  72,  74,  78,  84,  92;
98,  102, 104, 105, 108, 113, 120, 129;
136, 141, 144, 145, 147, 151, 157, 165, 175;
183, 189, 193, 195, 196, 199, 204, 211, 220, 231;
...

Partial sums of A130517 (when that sequence is regarded as a flattened triangle). Other versions are A212013, A212123, A213363, A213373.

Cf. A000292, A004006, A162630, A210984

a(n) = A210984(n)/2.

A213363 Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

1, 3, 4, 7, 8, 10, 14, 16, 19, 20, 25, 28, 32, 33, 35, 41, 45, 47, 54, 59, 60, 63, 68, 74, 82, 85, 86, 90, 92

Offset: 1

Omar E. Pol, Jun 23 2012

First differs from A212123 at a(12).

			Written as an irregular triangle in which row j is related to the j-th shell of nucleus. Note that row 4 has only one term. Triangle begins:
1;
3, 4;
7, 8, 10;
14;
16, 19, 20, 25;
28, 32, 33, 35, 41;
45, 47, 54, 59, 60, 63;
68, 74, 82, 85, 86, 90, 92;
...

Partial sums of A213361. Other versions are A210983, A212013, A213373.

Cf. A018226, A212121-A212124, A213362, A213364.

a(n) = A213364(n)/2.

A210984 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

Original entry on oeis.org

2, 6, 8, 14, 16, 20, 28, 32, 34, 40, 50, 56, 58, 62, 70, 82, 90, 94, 96, 102, 112, 126, 136, 142, 144, 148, 156, 168, 184, 196, 204, 208, 210, 216, 226, 240, 258, 272, 282, 288, 290, 294, 302, 314, 330, 350, 366, 378, 386, 390, 392, 398, 408, 422, 440, 462

Offset: 1

Omar E. Pol, Jul 14 2012

			Example 1: written as a triangle in which row i is related to the (i-1)st level of nucleus the sequence begins:
2;
6,     8;
14,   16,  20;
28,   32,  34,  40;
50,   56,  58,  62,  70;
82,   90,  94,  96, 102, 112;
126, 136, 142, 144, 148, 156, 168;
184, 196, 204, 208, 210, 216, 226, 240;
258, 272, 282, 288, 290, 294, 302, 314, 330;
350, 366, 378, 386, 390, 392, 398, 408, 422, 440;
...
Column 1 gives positive terms of A033547. Right border gives positive terms of A007290.
Example 2: written as an irregular triangle in which row j is related to the j-th shell of nucleus. In this case note that row 4 has only one term. Triangle begins:
2;
6,     8;
14,   16,  20;
28;
32,   34,  40;  50;
56,   58,  62,  70;  82;
90,   94,  96, 102, 112; 126;
136, 142, 144, 148, 156, 168; 184;
196, 204, 208, 210, 216, 226, 240; 258;
272, 282, 288, 290, 294, 302, 314, 330, 350;
366, 378, 386, 390, 392, 398, 408, 422, 440, 462;
...
First seven terms of right border give the "magic numbers" A018226.

Partial sums of A162630. Other versions are A212014, A212124, A213364, A213374.

Cf. A018226, A033547, A007290, A130517, A210983.

a(n) = 2*A210983(n).

cp's OEIS Frontend

A212121 Triangle read by rows in which row n lists the number of pairs of states of the subshells of the n-th shell of the nuclear shell model ordered by energy level in increasing order.

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A213364 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

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A212122 Triangle read by rows in which row n lists the number of states of the subshells of the n-th shell of the nuclear shell model ordered by energy level in increasing order.

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A212014 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

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A212123 Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

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A213361 Triangle read by rows in which row n lists the number of pairs of states of the subshells of the n-th shell of the nuclear shell model ordered by energy level in increasing order.

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A213374 Total number of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

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A210983 Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

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A213363 Total number of pairs of states of the first n subshells of the nuclear shell model in which the subshells are ordered by energy level in increasing order.

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