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.

A261743 Number of partitions of n where each part i is marked with a word of length i over a nonary alphabet whose letters appear in alphabetical order.

Original entry on oeis.org

1, 9, 126, 1299, 14211, 136611, 1373127, 12838293, 122478147, 1129559068, 10495764324, 95773104459, 877873080195, 7963150929030, 72400207009635, 654588661768353, 5924851016703093, 53460853371243261, 482688774419853026, 4350478100196378069, 39224153751141474936
Offset: 0

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Author

Alois P. Heinz, Aug 30 2015

Keywords

Crossrefs

Column k=9 of A261718.

Programs

  • Maple
    b:= proc(n, i) option remember; `if`(n=0, 1, `if`(i<1, 0,
          b(n, i-1)+`if`(i>n, 0, b(n-i, i)*binomial(i+8, 8))))
        end:
    a:= n-> b(n$2):
    seq(a(n), n=0..30);

Formula

a(n) ~ c * 9^n, where c = Product_{k>=2} 1/(1 - binomial(k+8,8)/9^k) = 3.23950351986835655716873222462341048089067679826... - Vaclav Kotesovec, Oct 11 2017, updated May 10 2021
G.f.: Product_{k>=1} 1 / (1 - binomial(k+8,8)*x^k). - Ilya Gutkovskiy, May 10 2021