A130517 -id:A130517 - cp's OEIS frontend

A220073 Mirror of the triangle A130517.

1, 1, 2, 2, 1, 3, 3, 1, 2, 4, 4, 2, 1, 3, 5, 5, 3, 1, 2, 4, 6, 6, 4, 2, 1, 3, 5, 7, 7, 5, 3, 1, 2, 4, 6, 8, 8, 6, 4, 2, 1, 3, 5, 7, 9, 9, 7, 5, 3, 1, 2, 4, 6, 8, 10, 10, 8, 6, 4, 2, 1, 3, 5, 7, 9, 11, 11, 9, 7, 5, 3, 1, 2, 4, 6, 8, 10, 12, 12, 10, 8, 6, 4, 2

Offset: 1

Reinhard Zumkeller, Dec 03 2012

T(n,k) = A130517(n,n-k+1), 1 <= k <= n;
T(n,n) = T(n,1) + 1.
From Boris Putievskiy, Jan 15 2013: (Start)
General case see A187760. Let m be natural number. Table T(n,k) n, k > 0, T(n,k)=n-k+1, if n>=k, T(n,k)=k-n+m-1, if n < k.  Table T(n,k) read by antidiagonals. The first column of the table T(n,1) is the sequence of the natural numbers A000027. In all columns with number k (k > 1) the segment with the length of (k-1): {m+k-2, m+k-3, ..., m}  shifts the sequence A000027. For m=1 the result is A220073, for m=2 the result is A143182. (End)
First inverse function (numbers of rows) for pairing function A209293. - Boris Putievskiy, Jan 28 2013

			From _Boris Putievskiy_, Jan 15 2013: (Start)
The start of the sequence as table:
1..1..2..3..4..5..6..7...
2..1..1..2..3..4..5..6...
3..2..1..1..2..3..4..5...
4..3..2..1..1..2..3..4...
5..4..3..2..1..1..2..3...
6..5..4..3..2..1..1..2...
7..6..5..4..3..2..1..1...
8..7..6..5..4..3..2..1...
. . .
The start of the sequence as triangle array read by rows:
1,
1, 2,
2, 1, 3,
3, 1, 2, 4,
4, 2, 1, 3, 5,
5, 3, 1, 2, 4, 6,
6, 4, 2, 1, 3, 5, 7,
7, 5, 3, 1, 2, 4, 6, 8,
. . .
Row number r contains r numbers: r-1, r-3,...,1,...r-2,r.
(End)

Reinhard Zumkeller, Rows n = 1..120 of triangle, flattened
Boris Putievskiy, Transformations [of] Integer Sequences And Pairing Functions arXiv:1212.2732 [math.CO], 2012.

Cf. A028310 (left edge), A000027 (right edge), A000012 (central terms), A000217 (row sums), A220075 (partial sums in rows), A002260, A000027, A143182, A187760, A209293.

a220073 n k = a220073_tabl !! (n-1) !! (k-1)
a220073_row n = a220073_tabl !! (n-1)
a220073_tabl = map reverse a130517_tabl

max = 13;
row[n_] := Join[Range[n, 1, -1], Range[max - n + 1]];
T = Array[row, max];
Table[T[[n - k + 1, k]], {n, 1, max}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Sep 11 2017 *)

T(1,1)=1, for n>1: T(n,k)=T(n-1,n-k+1), 1<=k

From Boris Putievskiy, Jan 15 2013: (Start)

For the general case

a(n) = |(t+1)^2 - 2n| + m*floor((t^2+3t+2-2n)/(t+1)),

where t = floor((-1+sqrt(8*n-7))/2).

For m = 2

a(n) = |(t+1)^2 - 2n| + floor((t^2+3t+2-2n)/(t+1)),

where t=floor((-1+sqrt(8*n-7))/2). (End)

A220053 Partial sums in rows of A130517, triangle read by rows.

Original entry on oeis.org

1, 2, 3, 3, 4, 6, 4, 6, 7, 10, 5, 8, 9, 11, 15, 6, 10, 12, 13, 16, 21, 7, 12, 15, 16, 18, 22, 28, 8, 14, 18, 20, 21, 24, 29, 36, 9, 16, 21, 24, 25, 27, 31, 37, 45, 10, 18, 24, 28, 30, 31, 34, 39, 46, 55, 11, 20, 27, 32, 35, 36, 38, 42, 48, 56, 66, 12, 22, 30

Offset: 1

Reinhard Zumkeller, Dec 03 2012

			1;
2, 3;
3, 4, 6;
4, 6, 7, 10;
5, 8, 9, 11, 15;
6, 10, 12, 13, 16, 21;
7, 12, 15, 16, 18, 22, 28;
8, 14, 18, 20, 21, 24, 29, 36;
9, 16, 21, 24, 25, 27, 31, 37, 45;
10, 18, 24, 28, 30, 31, 34, 39, 46, 55;
11, 20, 27, 32, 35, 36, 38, 42, 48, 56, 66;

Reinhard Zumkeller, Table of n, a(n) for n = 1..7260

Cf. A000027 (left edge), A000217 (right edge), A000290 (central terms), A002717 (row sums); A220075.

a220053 n k = a220053_tabl !! (n-1) !! (k-1)
a220053_row n = a220053_tabl !! (n-1)
a220053_tabl = map (scanl1 (+)) a130517_tabl
-- Reinhard Zumkeller, Dec 03 2012

T[n_, 1] := n;
T[n_, n_] := n-1;
T[n_, k_] := Abs[2k - n - If[2k <= n+1, 2, 1]];
row[n_] := Table[T[n, k], {k, 1, n}] // Accumulate;
Table[row[n], {n, 1, 12}] // Flatten (* Jean-François Alcover, Sep 23 2021 *)

T(n,k) = Sum_{i=1..k} A130517(n, i).

A375303 a(n) is the rank of row n of A130517 in a lexicographic permutation of [1, ..., n].

Original entry on oeis.org

0, 1, 4, 20, 108, 678, 4848, 39264, 355920, 3575640, 39454560, 474501600, 6178566240, 86606881200, 1300352981760, 20821540239360, 354184575816960, 6378546460970880, 121243261343500800, 2425719783585369600, 50955334461183398400, 1121303792572973856000, 25795667534014525593600

Offset: 1

Hugo Pfoertner, Aug 26 2024

nonn

Cf. A130517, A375302.

\\ uses functions a130517_row from A130517 and rank from A375302.
a(n) = rank(a130517_row(n))

A130598 A shell geometric model of the nucleus. The location of the magic numbers. A triangle.

Original entry on oeis.org

10, 1111, 10, 111111, 11, 1110, 11111110, 1111, 11, 111111, 1111111110, 111111, 11, 1111, 11111111, 111111111110, 11111111, 1111, 11, 111111, 1111111111, 11111111111110, 1111111111, 111111, 11, 1111, 11111111, 111111111111

Offset: 1

Omar E. Pol, Aug 10 2007

The magic numbers of the atomic nucleus: 2, 8, 20, 28, 50, 82, 126. 0 is the location of a magic number. 10 or 11 is equal to 2 protons (or neutrons). 1110 or 1111 is equal to 2+2 protons (or neutrons). 111111 is equal to 2+2+2 protons (or neutrons)... The 2D model is a triangle and a spiral. The 3D model is a double tetrahedron and a double spiral.

			......|----------------------- h -------------------|.....
......|.....|----------------- g --------------|....|.....
......|.....|.....|----------- f ---------|....|....|.....
......|.....|.....|....|------ d -----|...|....|....|.....
......|.....|.....|....|...|-- p -|...|...|....|....|.....
......|.....|.....|....|...|.. s .|...|...|....|....|.....
......|.....|.....|....|...|......|...|...|....|....|.....
......|.....|.....|....|......10......|...|....|....|.....
......|.....|.....|......1111....10.......|....|....|.....
......|.....|.......111111....11....1110.......|....|.....
......|........11111110..1111....11....111111.......|.....
.......1111111110...111111....11....1111...11111111.|.....
111111111110...11111111..1111....11....111111...1111111111
......|.....|.....|....|...|..|...|...|...|....|....|.....
......|.....|.....|....|...|..|1/2|...|...|....|....|.....
......|.....|.....|....|...|-- 3/2 ---|...|....|....|.....
......|.....|.....|....|------ 5/2 -------|....|....|.....
......|.....|.....|----------- 7/2 ------------|....|.....
......|.....|----------------- 9/2 -----------------|.....
......|---------------------- 11/2 -----------------------

Cf. A056951, A130517, A130556, A130602.

A130556 A model of the atomic nucleus (Shell model of nucleus). A triangle.

Original entry on oeis.org

1, 11, 1, 111, 1, 11, 1111, 11, 1, 111, 11111, 111, 1, 11, 1111, 111111, 1111, 11, 1, 111, 11111, 1111111, 11111, 111, 1, 11, 1111, 111111, 11111111, 111111, 1111, 11, 1, 111, 11111, 1111111

Offset: 1

Omar E. Pol, Aug 09 2007, Aug 12 2007

1 is equal to 2 protons, 11 is equal to 2+2 protons, 111 is equal to 2+2+2 protons...

Repunit numbers represent the subshells.

			A geometric model of the shell structure of nucleus:
...|----------------------.i.----------------------|
...|...|------------------.h.------------------|...|
...|...|...|--------------.g.--------------|...|...|
...|...|...|...|----------.f.----------|...|...|...|
...|...|...|...|...|------.d.------|...|...|...|...|
...|...|...|...|...|...|--.p.--|...|...|...|...|...|
...|...|...|...|...|...|...s...|...|...|...|...|...|
...|...|...|...|...|...|...|...|...|...|...|...|...|
...|...|...|...|...|...|.......|...|...|...|...|...|
...|...|...|...|...|.......1.......|...|...|...|...|
...|...|...|...|......11.......1.......|...|...|...|
...|...|...|......111......1......11.......|...|...|
...|...|.....1111.....11.......1......111......|...|
...|.....11111....111......1......11.....1111......|
....111111...1111.....11.......1......111....11111....
1111111..11111....111......1......11.....1111...111111
......................................................
...|...|...|...|...|...|...|...|...|...|...|...|...|
...|...|...|...|...|...|...|1/2|...|...|...|...|...|
...|...|...|...|...|...|----3/2----|...|...|...|...|
...|...|...|...|...|--------5/2--------|...|...|...|
...|...|...|...|------------7/2------------|...|...|
...|...|...|----------------9/2----------------|...|
...|...|-------------------11/2--------------------|
...|----------------------.13/2.--------------------

Cf. A056951, A130517, A130598, A130602.

A130602 A shell geometric model of the atomic nucleus.

Original entry on oeis.org

11, 1111, 11, 111111, 11, 1111, 11111111, 1111, 11, 111111, 1111111111, 111111, 11, 1111, 11111111, 111111111111, 11111111, 1111, 11, 111111, 1111111111, 11111111111111, 1111111111, 111111, 11, 1111, 11111111, 111111111111

Offset: 1

Omar E. Pol, Aug 10 2007, Aug 12 2007

nonn

11 is equal to 2 protons. 1111 is equal 2+2 protons. 111111 is equal 2+2+2 protons...

Repunit numbers represent the subshells.

			See the model in the entry: A130517, A130556.

Cf. A056951, A130517, A130556.

A162630 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, 2, 6, 10, 6, 2, 4, 8, 12, 8, 4, 2, 6, 10, 14, 10, 6, 2, 4, 8, 12, 16, 12, 8, 4, 2, 6, 10, 14, 18, 14, 10, 6, 2, 4, 8, 12, 16, 20, 16, 12, 8, 4, 2, 6, 10, 14, 18, 22, 18, 14, 10, 6, 2, 4, 8, 12, 16, 20, 24, 20, 16, 12, 8, 4, 2

Offset: 1

Omar E. Pol, Jul 10 2009

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), 2p_(1/2), etc. The numerators of the fractions are 1, 3, 1, 5, 1, 3, 7, 3, 1, ... then we add 1 to every numerator, so we have this sequence: 2, 4, 2, 6, 2, 4, 8, 4, 2, ... Other sequences that arise from this sequence are A A130517, A210983, A210984. - Omar E. Pol, Sep 02 2012

			A geometric shell model of the atomic nucleus:
   +---------------------- i ----------------------+
   |   +------------------ h ------------------+   |
   |   |   +-------------- g --------------+   |   |
   |   |   |   +---------- f ----------+   |   |   |
   |   |   |   |   +------ d ------+   |   |   |   |
   |   |   |   |   |   +-- p --+   |   |   |   |   |
   |   |   |   |   |   |   s   |   |   |   |   |   |
   |   |   |   |   |   |   |   |   |   |   |   |   |
   |   |   |   |   |   |       |   |   |   |   |   |
   |   |   |   |   |       2       |   |   |   |   |
   |   |   |   |       4       2       |   |   |   |
   |   |   |       6       2       4       |   |   |
   |   |       8       4       2       6       |   |
   |      10       6       2       4       8       |
      12       8       4       2       6      10
  14      10       6       2       4       8      12
   |   |   |   |   |   |   |   |   |   |   |   |   |
   |   |   |   |   |   |   +1/2+   |   |   |   |   |
   |   |   |   |   |   +--- 3/2 ---+   |   |   |   |
   |   |   |   |   +------- 5/2 -------+   |   |   |
   |   |   |   +----------- 7/2 -----------+   |   |
   |   |   +--------------- 9/2 ---------------+   |
   |   +------------------ 11/2 -------------------+
   +---------------------- 13/2 -----------------------

Boris Putievskiy, Transformations [of] Integer Sequences And Pairing Functions, 2012, arXiv:1212.2732 [math.CO], 2012.

Cf. A018226, A130517, A130556, A130598, A130602, A162626.

Other versions are A212012, A212122, A213362, A213372

t[n_, 1] := n; t[n_, n_] := n-1;
t[n_, k_] := Abs[2k - n - If[2k <= n+1, 2, 1]];
2 Table[t[n, k], {n, 1, 12}, {k, 1, n}] // Flatten (* Jean-François Alcover, Nov 17 2018 *)

a(n) = 2*A130517(n).
From Boris Putievskiy, Jan 16 2013: (Start)
a(n) = 2*(|2*A000027(n) - A003056(n)^2 - 2*A003056(n) - 3| + floor((2*A000027(n) - A003056(n)^2 - A003056(n))/(A003056(n) + 3))).
a(n) = 2*(|2*n - t*t - 2*t - 3| + floor((2*n - t*t - t)/(t+3))) where t = floor((-1 + sqrt(8*n-7))/2). (End)

Corrected by Omar E. Pol, Jul 13 2009
More terms from Omar E. Pol, Jul 14 2012
New name from Omar E. Pol, Sep 02 2012

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.

Original entry on oeis.org

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.

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).

A162522 First differences of magic numbers A018226.

Original entry on oeis.org

6, 12, 8, 22, 32, 44

Offset: 1

Omar E. Pol, Jul 06 2009

Sequence related to atomic nuclei.

Cf. A018226, A130517, A130556, A130598, A130602, A162521, A162523, A162524, A162525.

Showing 1-10 of 28 results. Next

cp's OEIS Frontend

A220073 Mirror of the triangle A130517.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Haskell

Mathematica

Formula

A220053 Partial sums in rows of A130517, triangle read by rows.

Views

Author

Keywords

Examples

Links

Crossrefs

Programs

Haskell

Mathematica

Formula

A375303 a(n) is the rank of row n of A130517 in a lexicographic permutation of [1, ..., n].

Views

Author

Keywords

Crossrefs

Programs

PARI

A130598 A shell geometric model of the nucleus. The location of the magic numbers. A triangle.

Views

Author

Keywords

Comments

Examples

Crossrefs

A130556 A model of the atomic nucleus (Shell model of nucleus). A triangle.

Views

Author

Keywords

Comments

Examples

Crossrefs

A130602 A shell geometric model of the atomic nucleus.

Views

Author

Keywords

Comments

Examples

Crossrefs

A162630 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.

Views

Author

Keywords

Comments

Examples

Links

Crossrefs

Programs

Mathematica

Formula

Extensions

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.

Views

Author

Keywords

Comments

Examples

Crossrefs

Formula

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.

Views

Author

Keywords

Comments

Examples

References

Links