A261844 Number of compositions of n into distinct parts where each part i is marked with a word of length i over a senary alphabet whose letters appear in alphabetical order.

1, 6, 21, 308, 798, 4116, 51114, 126288, 502947, 1912318, 26074881, 55301652, 210871038, 643901916, 2416831656, 32128430000, 64611765009, 218800524222, 625968110257, 1971079800312, 6127902153366, 88805517515284, 163129580373222, 530136843388056

Offset

0,2

Comments

Also matrices with six 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

Maple

b:= proc(n, i, p) option remember;
      `if`(i*(i+1)/2<n, 0, `if`(n=0, p!, b(n, i-1, p)+
      `if`(i>n, 0, b(n-i, i-1, p+1)*binomial(i+5, 5))))
    end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..30);

Crossrefs

Column k=6 of A261835.

Sequence in context: A213680 A164643 A190275 * A007594 A316775 A181593

Adjacent sequences: A261841 A261842 A261843 * A261845 A261846 A261847

Keyword

nonn

Author

Alois P. Heinz, Sep 03 2015

Status

approved