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 1-3 of 3 results.

A360037 Triangle read by rows. Number T(n, k) of partitions of the multiset [1, 1, 1, 2, 2, 2, ..., n, n, n] into k nonempty subsets, for 3 <= k <= 3n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 4, 10, 13, 7, 3, 1, 1, 14, 92, 221, 249, 172, 81, 25, 6, 1, 1, 50, 872, 4277, 8806, 9840, 6945, 3377, 1206, 325, 65, 10, 1, 1, 186, 8496, 85941, 320320, 585960, 627838, 442321, 221475, 82985, 24038, 5496, 995, 140, 15, 1
Offset: 1

Views

Author

Marko Riedel, Jan 22 2023

Keywords

Comments

A generalization of ordinary Stirling set numbers to multisets that contain some m instances each of n elements, here we have m=3.

Examples

			The triangular array starts:
[1]: 1;
[2]: 1,  1,  1,   1;
[3]: 1,  4, 10,  13,   7,   3,  1;
[4]: 1, 14, 92, 221, 249, 172, 81, 25, 6, 1;
		

References

  • F. Harary and E. Palmer, Graphical Enumeration, Academic Press, 1973.

Crossrefs

Row sums are A165434.

Programs

  • Maple
    read "a360037maple":  # see link
    A360037Row := n -> seq(T2(n, k, 3), k = 3..n*3): seq(A360037Row(n), n = 1..6);

A360038 Triangle read by rows. Number T(n, k) of partitions of the multiset [1, 1, 1, 1, 2, 2, 2, 2, ..., n, n, n, n] into k nonempty subsets, for 4 <= k <= 4n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 4, 11, 19, 22, 13, 7, 3, 1, 1, 14, 117, 445, 873, 1002, 805, 483, 226, 81, 25, 6, 1, 1, 51, 1387, 12567, 47986, 96620, 120970, 104942, 67901, 34385, 14150, 4817, 1371, 325, 65, 10, 1, 1, 201, 18171, 396571, 3053216, 11003801, 22360580, 29114463, 26607981, 18227245, 9816458, 4301588, 1572206, 487670, 129880, 29828, 5901, 995, 140, 15, 1
Offset: 1

Views

Author

Marko Riedel, Jan 22 2023

Keywords

Comments

A generalization of ordinary Stirling set numbers to multisets that contain some m instances each of n elements, here we have m=4.

Examples

			The triangular array starts:
[1]: 1;
[2]: 1,  1,   1,   1,   1;
[3]: 1,  4,  11,  19,  22,   13,   7,   3,   1;
[4]: 1, 14, 117, 445, 873, 1002, 805, 483, 226, 81, 25, 6, 1;
		

References

  • F. Harary and E. Palmer, Graphical Enumeration, Academic Press, 1973.

Crossrefs

Cf. A098233, A360037, A360039, A165435 (row sums).

A098233 Consider the family of ordinary multigraphs. Sequence gives the triangle read by rows giving coefficients of polynomials arising from enumeration of those multigraphs on n edges.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 4, 7, 3, 1, 1, 13, 46, 47, 25, 6, 1, 1, 40, 295, 587, 516, 235, 65, 10, 1, 1, 121, 1846, 6715, 9690, 7053, 3006, 800, 140, 15, 1, 1, 364, 11347, 73003, 170051, 189458, 119211, 46795, 12201, 2170, 266, 21, 1, 1, 1093, 68986, 768747
Offset: 0

Views

Author

N. J. A. Sloane, Oct 26 2004

Keywords

Comments

Also gives number T(n, k) of partitions of the multiset {1, 1, 2, 2, ..., n, n} into k nonempty subsets, for 2 <= k <= 2n. - Marko Riedel, Jan 22 2023

Examples

			The first few polynomials are:
  1,
  x^2,
  x^2+x^3+x^4,
  x^2+4x^3+7x^4+3x^5+x^6,
  x^2+13x^3+46x^4+47x^5+25x^6+6x^7+x^8,
  x^2+40x^3+295x^4+587x^5+516x^6+235x^7+65x^8+10x^9+x^10,
  ...
Triangle starts:
  1;
  1;
  1,  1,   1;
  1,  4,   7,   3,   1;
  1, 13,  46,  47,  25,   6,  1;
  1, 40, 295, 587, 516, 235, 65, 10, 1;
  ...
		

References

  • G. Paquin, Dénombrement de multigraphes enrichis, Mémoire, Math. Dept., Univ. Québec à Montréal, 2004.

Crossrefs

Cf. A360037, A360038, A360039, A020554 (row sums).
Showing 1-3 of 3 results.