cp's OEIS Frontend

A320217 Number of multisets of nonempty words with a total of n letters over septenary alphabet such that all letters occur at least once in the multiset.

%I A320217 #4 Oct 07 2018 14:47:52
%S A320217 37633,1394414,30044014,493609088,6864854521,85265606888,976232236182,
%T A320217 10515038040403,108038163343516,1069407324384749,10272179741315583,
%U A320217 96275040557582796,884152621318502522,7982464409593829883,71036604818774830215,624423552992566806913
%N A320217 Number of multisets of nonempty words with a total of n letters over septenary alphabet such that all letters occur at least once in the multiset.
%H A320217 Alois P. Heinz, <a href="/A320217/b320217.txt">Table of n, a(n) for n = 7..1000</a>
%p A320217 b:= proc(n, k) option remember; `if`(n=0, 1, add(add(
%p A320217       d*k^d, d=numtheory[divisors](j))*b(n-j, k), j=1..n)/n)
%p A320217     end:
%p A320217 a:= n-> (k-> add(b(n, k-i)*(-1)^i*binomial(k, i), i=0..k))(7):
%p A320217 seq(a(n), n=7..25);
%Y A320217 Column k=7 of A257740.
%Y A320217 Cf. A320208.
%K A320217 nonn
%O A320217 7,1
%A A320217 _Alois P. Heinz_, Oct 07 2018