cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Previous Showing 11-15 of 15 results.

A210956 Triangle read by rows: T(n,k) = sum of all parts <= k in the last section of the set of partitions of n.

Original entry on oeis.org

1, 1, 3, 2, 2, 5, 3, 7, 7, 11, 5, 7, 10, 10, 15, 7, 15, 21, 25, 25, 31, 11, 17, 23, 27, 32, 32, 39, 15, 31, 40, 52, 57, 63, 63, 71, 22, 36, 54, 62, 72, 78, 85, 85, 94, 30, 60, 78, 98, 113, 125, 132, 140, 140, 150, 42, 72, 102, 122, 142, 154, 168, 176, 185, 185, 196
Offset: 1

Views

Author

Omar E. Pol, May 01 2012

Keywords

Comments

Row n lists the partial sums of row n of triangle A207383.

Examples

			Triangle begins:
1;
1,   3;
2,   2, 5;
3,   7, 7, 11;
5,   7, 10, 10, 15;
7,  15, 21, 25, 25, 31;
11, 17, 23, 27, 32, 32, 39;
15, 31, 40, 52, 57, 63, 63, 71;
22, 36, 54, 62, 72, 78, 85, 85, 94;

Links

Crossrefs

Column 1 is A000041. Right border gives A138879.
Cf. A135010, A138121, A182703, A206437, A206562, A207031, A207032, 207383, 208476, A210948, A210955.

Programs

  • PARI
    Row(n)={my(v=vector(n)); v[1]=numbpart(n-1); if(n>1, forpart(p=n, for(k=1, #p, v[p[k]]++), [2,n])); for(k=2, n, v[k]=v[k-1]+k*v[k]); v}
{ for(n=1, 10, print(Row(n))) }

Formula

T(n,k) = Sum_{j=1..k} A207383(n,j).

Extensions

Terms a(46) and beyond from Andrew Howroyd, Feb 19 2020

A208476 Triangle read by rows: T(n,k) = total sum of odd/even parts >= k in the last section of the set of partitions of n, if k is odd/even.

Original entry on oeis.org

1, 1, 2, 5, 0, 3, 3, 8, 0, 4, 13, 2, 8, 0, 5, 13, 18, 6, 10, 0, 6
Offset: 1

Views

Author

Omar E. Pol, Feb 28 2012

Keywords

Comments

Essentially this sequence is related to A206562 in the same way as A207032 is related to A207031 and also in the same way as A206563 is related to A181187. See the calculation in the example section of A206563.

Examples

			Triangle begins:
1;
1,   2;
5,   0,  3;
3,   8,  0,  4;
13,  2,  8,  0,  5;
13, 18,  6, 10,  0,  6;

Crossrefs

Right border is A000027.
Cf. A135010, A182703, A206562, A207031, A207032, A207383, A208475.

A210955 Triangle read by rows: T(n,k) = total number of parts <= k in the last section of the set of partitions of n.

Original entry on oeis.org

1, 1, 2, 2, 2, 3, 3, 5, 5, 6, 5, 6, 7, 7, 8, 7, 11, 13, 14, 14, 15, 11, 14, 16, 17, 18, 18, 19, 15, 23, 26, 29, 30, 31, 31, 32, 22, 29, 35, 37, 39, 40, 41, 41, 42, 30, 45, 51, 56, 59, 61, 62, 63, 63, 64, 42, 57, 67, 72, 76, 78, 80, 81, 82, 82, 83
Offset: 1

Views

Author

Omar E. Pol, May 01 2012

Keywords

Comments

Row n lists the partial sums of row n of triangle A182703.

Examples

			1,
1,   2,
2,   2,  3,
3,   5,  5,  6,
5,   6,  7,  7,  8,
7,  11, 13, 14, 14, 15,
11, 14, 16, 17, 18, 18, 19,
15, 23, 26, 29, 30, 31, 31, 32,
22, 29, 35, 37, 39, 40, 41, 41, 42;

Crossrefs

Column 1 is A000041. Right border gives A138137.
Cf. A135010, A138121, A182703, A206437, A206562, A207031, A207032, A207383, A208476, A210947, A210956.

Formula

T(n,k) = Sum_{j=1..k} A182703(n,j).

Extensions

More terms from Alois P. Heinz, May 25 2013

A230440 Triangle read by rows in which row n lists A000041(n-1) 1's followed by the list of partitions of n that do not contain 1 as a part in colexicographic order.

Original entry on oeis.org

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

Views

Author

Omar E. Pol, Oct 18 2013

Keywords

Comments

The n-th row of triangle lists the parts of the n-th section of the set of partitions of any integer >= n. For the definition of "section" see A135010.

Examples

			Illustration of initial terms (row = 1..6). The table shows the six sections of the set of partitions of 6 in three ways. Note that before the dissection, the set of partitions was in colexicographic order, see A211992. More generally, in a master model, the six sections of the set of partitions of 6 also can be interpreted as the first six sections of the set of partitions of any integer >= 6.
---------------------------------------------------------
n  j     Diagram          Parts              Parts
---------------------------------------------------------
.         _
1  1     |_|              1;                 1;
.           _
2  1      _| |              1,                 1,
2  2     |_ _|              2;               2;
.             _
3  1         | |              1,                 1,
3  2      _ _| |              1,               1,
3  3     |_ _ _|              3;             3;
.               _
4  1           | |              1,                 1,
4  2           | |              1,               1,
4  3      _ _ _| |              1,             1,
4  4     |_ _|   |            2,2,           2,2,
4  5     |_ _ _ _|              4;           4;
.                 _
5  1             | |              1,                 1,
5  2             | |              1,               1,
5  3             | |              1,             1,
5  4             | |              1,             1,
5  5      _ _ _ _| |              1,           1,
5  6     |_ _ _|   |            3,2,         3,2,
5  7     |_ _ _ _ _|              5;         5;
.                   _
6  1               | |              1,                 1,
6  2               | |              1,               1,
6  3               | |              1,             1,
6  4               | |              1,             1,
6  5               | |              1,           1,
6  6               | |              1,           1,
6  7      _ _ _ _ _| |              1,         1,
6  8     |_ _|   |   |          2,2,2,       2,2,2,
6  9     |_ _ _ _|   |            4,2,       4,2,
6  10    |_ _ _|     |            3,3,       3,3,
6  11    |_ _ _ _ _ _|              6;       6;
...
Triangle begins:
[1];
[1],[2];
[1],[1],[3];
[1],[1],[1],[2,2],[4];
[1],[1],[1],[1],[1],[3,2],[5];
[1],[1],[1],[1],[1],[1],[1],[2,2,2],[4,2],[3,3],[6];
...

Crossrefs

Positive terms of A228716.
Row n has length A138137(n).
Row sums give A138879.
Right border gives A000027.
Cf. A000041, A135010, A138121, A141285, A182703, A187219, A193870, A194446, A206437, A207031, A207034, A207383, A207379, A211009.

A228527 Triangle read by rows: T(n,k) is the sum of all parts of size k of the n-th section of the set of compositions ( ordered partitions) of any integer >= n.

Original entry on oeis.org

1, 1, 2, 3, 2, 3, 7, 6, 3, 4, 16, 14, 9, 4, 5, 36, 32, 21, 12, 5, 6, 80, 72, 48, 28, 15, 6, 7, 176, 160, 108, 64, 35, 18, 7, 8, 384, 352, 240, 144, 80, 42, 21, 8, 9, 832, 768, 528, 320, 180, 96, 49, 24, 9, 10, 1792, 1664, 1152, 704, 400, 216, 112, 56, 27, 10, 11
Offset: 1

Views

Author

Omar E. Pol, Sep 01 2013

Keywords

Comments

In other words, T(n,k) is the sum of all parts of size k of the last section of the set of compositions (ordered partitions) of n.
For the definition of "section of the set of compositions" see A228524.
The equivalent sequence for partitions is A207383.

Examples

			Illustration (using the colexicograpical order of compositions A228525) of the four sections of the set of compositions of 4:
.
.            1      2        3          4
.            _      _        _          _
.           |_|   _| |      | |        | |
.                |_ _|   _ _| |        | |
.                       |_|   |        | |
.                       |_ _ _|   _ _ _| |
.                                |_| |   |
.                                |_ _|   |
.                                |_|     |
.                                |_ _ _ _|
.
For n = 4 and k = 2, T(4,2) = 6 because there are 3 parts of size 2 in the last section of the set of compositions of 4, so T(4,2) = 3*2 = 6, see below:
--------------------------------------------------------
.                         The last section      Sum of
.   Composition of 4        of the set of      parts of
.                         compositions of 4     size k
. --------------------   -------------------
.            Diagram             Diagram    k = 1 2 3 4
. ------------------------------------------------------
.            _ _ _ _                    _
.  1+1+1+1  |_| | | |         1        | |      1 0 0 0
.    2+1+1  |_ _| | |         1        | |      1 0 0 0
.    1+2+1  |_|   | |         1        | |      1 0 0 0
.      3+1  |_ _ _| |         1   _ _ _| |      1 0 0 0
.    1+1+2  |_| |   |     1+1+2  |_| |   |      2 2 0 0
.      2+2  |_ _|   |       2+2  |_ _|   |      0 4 0 0
.      1+3  |_|     |       1+3  |_|     |      1 0 3 0
.        4  |_ _ _ _|         4  |_ _ _ _|      0 0 0 4
.                                              ---------
.                      Column sums give row 4:  7,6,3,4
.
Triangle begins:
1;
1,       2;
3,       2,    3;
7,       6,    3,   4;
16,     14,    9,   4,   5;
36,     32,   21,  12,   5,   6;
80,     72,   48,  28,  15,   6,   7;
176,   160,  108,  64,  35,  18,   7,  8;
384,   352,  240, 144,  80,  42,  21,  8,  9;
832,   768,  528, 320, 180,  96,  49, 24,  9, 10;
1792, 1664, 1152, 704, 400, 216, 112, 56, 27, 10, 11;
...

Crossrefs

Column 1 is A045891. Row sums give A001792.
Cf. A011782, A135010, A207383, A221876, A228350, A228366, A228370, A228524, A228526.

Formula

T(n,k) = k*A045891(n-k) = k*A228524(n,k), n>=1, 1<=k<=n.
Previous Showing 11-15 of 15 results.

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