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.

Showing 1-5 of 5 results.

A327262 a(n) is the sum of all parts of all partitions of n into consecutive parts that differ by 4.

Original entry on oeis.org

1, 2, 3, 4, 5, 12, 7, 16, 9, 20, 11, 24, 13, 28, 30, 32, 17, 54, 19, 40, 42, 44, 23, 72, 25, 52, 54, 84, 29, 90, 31, 96, 66, 68, 35, 144, 37, 76, 78, 120, 41, 126, 43, 132, 135, 92, 47, 192, 49, 150, 102, 156, 53, 162, 110, 168, 114, 116, 59, 300, 61, 124, 126, 192, 130, 264, 67, 204, 138, 210
Offset: 1

Views

Author

Omar E. Pol, Apr 30 2020

Keywords

Comments

The one-part partition n = n is included in the count.

Examples

			For n = 28 there are three partitions of 28 into consecutive parts that differ by 4, including 28 as a valid partition. They are [28], [16, 12] and [13, 9, 5, 1]. The sum of the parts is [28] + [16 + 12] + [13 + 9 + 5 + 1] = 84, so a(28) = 84.
		

Crossrefs

Sequences of the same family where the parts differs by k are: A038040 (k=0), A245579 (k=1), A060872 (k=2), A334463 (k=3), this sequence (k=4), A334733 (k=5).

Programs

  • Mathematica
    pn4[n_]:=Total[Flatten[Select[IntegerPartitions[n],Union[Abs[Differences[#]]]=={4}&]]]+n; Array[pn4,70] (* Harvey P. Dale, Nov 26 2023 *)

Formula

a(n) = n*A334461(n).

A334953 a(n) is the sum of all parts of all partitions of n into consecutive parts that differ by 6.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 16, 9, 20, 11, 24, 13, 28, 15, 32, 17, 36, 19, 40, 42, 44, 23, 72, 25, 52, 54, 56, 29, 90, 31, 64, 66, 68, 35, 108, 37, 76, 78, 120, 41, 126, 43, 132, 90, 92, 47, 192, 49, 100, 102, 156, 53, 162, 55, 168, 114, 116, 59, 240, 61, 124, 126, 192, 130, 198, 67, 204, 138, 210
Offset: 1

Views

Author

Omar E. Pol, May 27 2020

Keywords

Comments

The one-part partition n = n is included in the count.

Examples

			For n = 24 there are three partitions of 24 into consecutive parts that differ by 6, including 24 as a valid partition. They are [24], [15, 9] and [14, 8, 2]. The sum of all parts is [24] + [15 + 9] + [14 + 8 + 2] = 72, so a(24) = 72.
		

Crossrefs

Sequences of the same family where the parts differs by k are: A038040 (k=0), A245579 (k=1), A060872 (k=2), A334463 (k=3), A327262 (k=4), A334733 (k=5), this sequence (k=6).

Formula

a(n) = n*A334948(n).

A334733 a(n) is the sum of all parts of all partitions of n into consecutive parts that differ by 5.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 14, 8, 18, 10, 22, 12, 26, 14, 30, 16, 34, 36, 38, 20, 63, 22, 46, 48, 50, 26, 81, 28, 58, 60, 62, 32, 99, 68, 70, 72, 74, 76, 117, 40, 82, 126, 86, 44, 135, 92, 94, 96, 98, 100, 153, 52, 106, 162, 165, 56, 171, 116, 118, 180, 122, 124, 189, 64, 195, 198, 134, 68, 207, 210
Offset: 1

Views

Author

Omar E. Pol, May 09 2020

Keywords

Comments

The one-part partition n = n is included in the count.

Examples

			For n = 27 there are three partitions of 27 into consecutive parts that differ by 5, including 27 as a valid partition. They are [27], [16, 11] and [14, 9, 4]. The sum of all parts is [27] + [16 + 11] + [14 + 9 + 4] = 81, so a(27) = 81.
		

Crossrefs

Sequences of the same family where the parts differs by k are: A038040 (k=0), A245579 (k=1), A060872 (k=2), A334463 (k=3), A327262 (k=4), this sequence (k=5).

Formula

a(n) = n*A334541(n).

A334945 Irregular triangle read by rows: T(n,k), n >= 1, k >= 1, in which column k lists successive blocks of k consecutive integers that differ by 3, where the m-th block starts with m, m >= 1, and the first element of column k is in the row that is the k-th pentagonal number (A000326).

Original entry on oeis.org

1, 2, 3, 4, 5, 1, 6, 4, 7, 2, 8, 5, 9, 3, 10, 6, 11, 4, 12, 7, 1, 13, 5, 4, 14, 8, 7, 15, 6, 2, 16, 9, 5, 17, 7, 8, 18, 10, 3, 19, 8, 6, 20, 11, 9, 21, 9, 4, 22, 12, 7, 1, 23, 10, 10, 4, 24, 13, 5, 7, 25, 11, 8, 10, 26, 14, 11, 2, 27, 12, 6, 5, 28, 15, 9, 8, 29, 13, 12, 11, 30, 16, 7, 3
Offset: 1

Views

Author

Omar E. Pol, May 27 2020

Keywords

Comments

This triangle can be interpreted as a table of partitions into consecutive parts that differ by 3 (see the Example section).
Also, every triangle of this family has the property that starting from row n the sum of k positive and consecutive terms in the column k is equal to n. - Omar E. Pol, Dec 18 2020

Examples

			Triangle begins:
   1;
   2;
   3;
   4;
   5,  1;
   6,  4;
   7,  2;
   8,  5;
   9,  3;
  10,  6;
  11,  4;
  12,  7,  1;
  13,  5,  4;
  14,  8,  7;
  15,  6,  2;
  16,  9,  5;
  17,  7,  8;
  18, 10,  3;
  19,  8,  6;
  20, 11,  9;
  21,  9,  4;
  22, 12,  7,  1;
...
Figures A..G show the location (in the columns of the table) of the partitions of n = 1..7 (respectively) into consecutive parts that differ by 3:
.   -----------------------------------------------------
Fig:   A     B     C     D       E        F        G
.   -----------------------------------------------------
. n:   1     2     3     4       5        6        7
Row -----------------------------------------------------
1   | [1];|  1; |  1; |  1; |  1;     |  1;   |  1;     |
2   |     | [2];|  2; |  2; |  2;     |  2;   |  2;     |
3   |     |     | [3];|  3; |  3;     |  3;   |  3;     |
4   |     |     |     | [4];|  4;     |  4;   |  4;     |
5   |     |     |     |     | [5],[1];|  5, 1;|  5,  1; |
6   |     |     |     |     |  6, [4];| [6],4;|  6,  4; |
7   |     |     |     |     |         |       | [7],[2];|
8   |     |     |     |     |         |       |  8, [5];|
.   -----------------------------------------------------
Figure G: for n = 7 the partitions of 7 into consecutive parts that differ by 3 (but with the parts in increasing order) are [7] and [2, 5]. These partitions have one part and two parts respectively. On the other hand  we can find the mentioned partitions in the columns 1 and 2 of this table, starting at the row 7.
.
Illustration of initial terms arranged into a triangular structure:
.                                                           _
.                                                         _|1|
.                                                       _|2  |
.                                                     _|3    |
.                                                   _|4     _|
.                                                 _|5      |1|
.                                               _|6       _|4|
.                                             _|7        |2  |
.                                           _|8         _|5  |
.                                         _|9          |3    |
.                                       _|10          _|6    |
.                                     _|11           |4     _|
.                                   _|12            _|7    |1|
.                                 _|13             |5      |4|
.                               _|14              _|8     _|7|
.                             _|15               |6      |2  |
.                           _|16                _|9      |5  |
.                         _|17                 |7       _|8  |
.                       _|18                  _|10     |3    |
.                     _|19                   |8        |6    |
.                   _|20                    _|11      _|9    |
.                 _|21                     |9        |4     _|
.                |22                       |12       |7    |1|
...
The number of horizontal line segments in the n-th row of the diagram equals A117277(n), the number of partitions of n into consecutive parts that differ by 3.
		

Crossrefs

Tables of the same family where the consecutive parts differ by d are A010766 (d=0), A286001 (d=1), A332266 (d=2), this sequence (d=3), A334618(d=4).

A334467 Square array read by antidiagonals upwards: T(n,k) is the sum of all parts of all partitions of n into consecutive parts that differ by k, with n >= 1, k >= 0.

Original entry on oeis.org

1, 4, 1, 6, 2, 1, 12, 6, 2, 1, 10, 4, 3, 2, 1, 24, 10, 8, 3, 2, 1, 14, 12, 5, 4, 3, 2, 1, 32, 14, 12, 10, 4, 3, 2, 1, 27, 8, 7, 6, 5, 4, 3, 2, 1, 40, 27, 16, 14, 12, 5, 4, 3, 2, 1, 22, 20, 18, 8, 7, 6, 5, 4, 3, 2, 1, 72, 22, 20, 18, 16, 14, 6, 5, 4, 3, 2, 1, 26, 24, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1
Offset: 1

Views

Author

Omar E. Pol, May 05 2020

Keywords

Examples

			Array begins:
     k  0   1   2   3   4   5   6   7   8   9  10
   n +------------------------------------------------
   1 |  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1, ...
   2 |  4,  2,  2,  2,  2,  2,  2,  2,  2,  2,  2, ...
   3 |  6,  6,  3,  3,  3,  3,  3,  3,  3,  3,  3, ...
   4 | 12,  4,  8,  4,  4,  4,  4,  4,  4,  4,  4, ...
   5 | 10, 10,  5, 10,  5,  5,  5,  5,  5,  5,  5, ...
   6 | 24, 12, 12,  6, 12,  6,  6,  6,  6,  6,  6, ...
   7 | 14, 14,  7, 14,  7, 14,  7,  7,  7,  7,  7, ...
   8 | 32,  8, 16,  8, 16,  8, 16,  8,  8,  8,  8, ...
   9 | 27, 27, 18, 18,  9, 18,  9, 18,  9,  9,  9, ...
  10 | 40, 20, 20, 10, 20, 20, 20, 10, 20, 10, 10, ...
...
		

Crossrefs

Columns k: A038040 (k=0), A245579 (k=1), A060872 (k=2), A334463 (k=3), A327262 (k=4), A334733 (k=5), A334953 (k=6).
Every diagonal starting with 1 gives A000027.
Sequences of number of parts related to column k: A000203 (k=0), A204217 (k=1), A066839 (k=2) (conjectured), A330889 (k=3), A334464 (k=4), A334732 (k=5), A334949 (k=6).
Sequences of number of partitions related to column k: A000005 (k=0), A001227 (k=1), A038548 (k=2), A117277 (k=3), A334461 (k=4), A334541 (k=5), A334948 (k=6).
Polygonal numbers related to column k: A001477 (k=0), A000217 (k=1), A000290 (k=2), A000326 (k=3), A000384 (k=4), A000566 (k=5), A000567 (k=6).

Programs

  • Mathematica
    nmax = 13;
    col[k_] := col[k] = CoefficientList[Sum[x^(n(k n - k + 2)/2 - 1)/(1 - x^n), {n, 1, nmax}] + O[x]^nmax, x];
    T[n_, k_] := n col[k][[n]];
    Table[T[n-k, k], {n, 1, nmax}, {k, 0, n-1}] // Flatten (* Jean-François Alcover, Nov 30 2020 *)

Formula

T(n,k) = n*A323345(n,k).
Showing 1-5 of 5 results.