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.

A144509 a(n) = total number of partitions of [1, 2, ..., k] into exactly n blocks, each of size 1, 2, ..., 5, for 0 <= k <= 5n.

Original entry on oeis.org

1, 5, 456, 405408, 1495388159, 15467641899285, 361207016885536095, 16557834064546698285496, 1350410785161120363519024709, 182141025850694258874753732988078, 38395944834298393218465758049745918098, 12093097322244029427838390643054170162054258, 5485321312184901565806045962453632525844948020084
Offset: 0

Views

Author

David Applegate and N. J. A. Sloane, Dec 15 2008

Keywords

Comments

Also, number of scenarios in the Gift Exchange Game when a gift can be stolen at most 4 times. - N. J. A. Sloane, Jan 25 2017

Crossrefs

The gift scenarios sequences when a gift can be stolen at most s times, for s = 1..9, are A001515, A144416, A144508, A144509, A149187, A281358, A281359, A281360, A281361.

Programs

  • Mathematica
    t[n_, n_] = 1; t[n_ /; n >= 0, k_] /; 0 <= k <= 5*n := t[n, k] = Sum[(1/j!)*Product[k - m, {m, 1, j}]*t[n - 1, k - j - 1], {j, 0, 4}]; t[, ] = 0; a[n_] := Sum[t[n, k], {k, 0, 5*n}]; Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Feb 18 2017 *)
  • PARI
    {a(n) = sum(i=n, 5*n, i!*polcoef(sum(j=1, 5, x^j/j!)^n, i))/n!} \\ Seiichi Manyama, May 22 2019