A261846 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.

1, 8, 36, 696, 2250, 14712, 245508, 737352, 3644355, 17376832, 325225824, 823612736, 3820113552, 14264475648, 66782014272, 1254553664640, 2949123559125, 12008271483720, 41150373332932, 157262062899640, 608878151760410, 12804954311547288, 27181470392583156

Offset

0,2

Comments

Also matrices with eight 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+7, 7))))
    end:
a:= n-> b(n$2, 0):
seq(a(n), n=0..25);

Crossrefs

Column k=8 of A261835.

Sequence in context: A203020 A276175 A050536 * A110215 A281465 A302619

Adjacent sequences: A261843 A261844 A261845 * A261847 A261848 A261849

Keyword

nonn

Author

Alois P. Heinz, Sep 03 2015

Status

approved