A320211 - OEIS

%I #7 Oct 07 2018 14:54:41

%S 58941091,4097382940,159454061270,4587784661870,108909499300650,

%T 2259736176893470,42433681634931005,737876928284127870,

%U 12073172284265618005,188049325030487680920,2812707955072045999940,40672129029056125818340,571583937930987524954470

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

%H Alois P. Heinz, <a href="/A320211/b320211.txt">Table of n, a(n) for n = 10..975</a>

%p h:= proc(n, i, k) option remember; `if`(n=0, 1, `if`(i<1, 0,

%p       add(h(n-i*j, i-1, k)*binomial(k^i, j), j=0..n/i)))

%p     end:

%p a:= n-> (k-> add((-1)^i*binomial(k, i)*h(n$2, k-i), i=0..k))(10):

%p seq(a(n), n=10..25);

%Y Column k=10 of A319501.

%Y Cf. A320220.

%K nonn

%O 10,1

%A _Alois P. Heinz_, Oct 07 2018