A261845 Number of compositions of n into distinct parts where each part i is marked with a word of length i over a septenary alphabet whose letters appear in alphabetical order.

1, 7, 28, 476, 1386, 8106, 117936, 322764, 1440579, 6172495, 99773646, 232110704, 981073576, 3329628176, 14040114012, 224848217580, 490210909629, 1828885568055, 5750093241172, 20040621544916, 69910543160794, 1238596672832718, 2451410591056280, 8705347941656016

Offset: 0

Author

Alois P. Heinz, Sep 03 2015

Keywords

• nonn

Comments

Also matrices with seven rows of nonnegative integers with distinct positive column sums and total element sum n.

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..5000

Crossrefs

Column k=7 of A261835.

Programs

Maple

b:= proc(n, i, p) option remember;
      `if`(i*(i+1)/2n, 0, b(n-i, i-1, p+1)*binomial(i+6, 6))))
    end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..25);