cp's OEIS Frontend

A320209 Number of sets of nonempty words with a total of n letters over octonary alphabet such that all letters occur at least once in the set.

%I A320209 #7 Oct 07 2018 14:50:41
%S A320209 394353,18235680,484092688,9697863856,163046201132,2430540970008,
%T A320209 33194557467204,424251626739144,5148887208055692,59963231946871288,
%U A320209 675318621308265328,7398542789316786184,79210967706138213860,831754864387299725168,8590788276593760698232
%N A320209 Number of sets of nonempty words with a total of n letters over octonary alphabet such that all letters occur at least once in the set.
%H A320209 Alois P. Heinz, <a href="/A320209/b320209.txt">Table of n, a(n) for n = 8..1000</a>
%p A320209 h:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0,
%p A320209       add(h(n-i*j, i-1, k)*binomial(k^i, j), j=0..n/i)))
%p A320209     end:
%p A320209 a:= n-> (k-> add((-1)^i*binomial(k, i)*h(n$2, k-i), i=0..k))(8):
%p A320209 seq(a(n), n=8..25);
%Y A320209 Column k=8 of A319501.
%Y A320209 Cf. A320218.
%K A320209 nonn
%O A320209 8,1
%A A320209 _Alois P. Heinz_, Oct 07 2018