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.

A261859 Number of compositions of n into distinct parts where each part i is marked with a word of length i over an octonary alphabet whose letters appear in alphabetical order and all letters occur at least once in the composition.

Original entry on oeis.org

2873, 66904, 4351388, 20331080, 157483354, 901563512, 6174438308, 180660353288, 511805155863, 2507827775824, 10089884785056, 44796664928048, 200977872433624, 5149800722642960, 11741438872834432, 48645418597510928, 159659060979170671, 593940633500376248
Offset: 8

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Author

Alois P. Heinz, Sep 03 2015

Keywords

Comments

Also number of matrices with eight rows of nonnegative integer entries and without zero rows or columns such that the sum of all entries is equal to n and the column sums are distinct.

Crossrefs

Column k=8 of A261836.

Programs

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

Formula

a(n) = A261836(n,8).