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.

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A359107 Triangle read by rows, T(n, k) = Sum_{j=0..k} Stirling2(n, j) = Sum_{j=0..k} A048993(n, j).

Original entry on oeis.org

1, 0, 1, 0, 1, 2, 0, 1, 4, 5, 0, 1, 8, 14, 15, 0, 1, 16, 41, 51, 52, 0, 1, 32, 122, 187, 202, 203, 0, 1, 64, 365, 715, 855, 876, 877, 0, 1, 128, 1094, 2795, 3845, 4111, 4139, 4140, 0, 1, 256, 3281, 11051, 18002, 20648, 21110, 21146, 21147
Offset: 0

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Author

Peter Luschny, Dec 27 2022

Keywords

Comments

T(n, k) is the number of partitions of an n-set that contain at most k nonempty subsets.

Examples

			Triangle T(n, k) starts:
[0] [1]
[1] [0, 1]
[2] [0, 1,   2]
[3] [0, 1,   4,    5]
[4] [0, 1,   8,   14,    15]
[5] [0, 1,  16,   41,    51,    52]
[6] [0, 1,  32,  122,   187,   202,   203]
[7] [0, 1,  64,  365,   715,   855,   876,   877]
[8] [0, 1, 128, 1094,  2795,  3845,  4111,  4139,  4140]
[9] [0, 1, 256, 3281, 11051, 18002, 20648, 21110, 21146, 21147]
		

Crossrefs

Cf. A048993, A000110 (T(n, n)), A359355 (T(2*n, n)), A359109 (row sums).
Without column k=0 the same as A102661.

Programs

  • Maple
    with(ListTools): ps := L -> PartialSums(L):
    Flatten([seq(ps([seq(Stirling2(n, k), k = 0..n)]), n = 0..10)]);
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