cp's OEIS Frontend

A245858 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 5.

%I A245858 #6 Aug 04 2014 13:04:47
%S A245858 1,0,0,0,0,252,924,1584,2574,4004,762762,6062784,31868200,121314312,
%T A245858 399096216,12936646128,167685283332,1429020461484,9754485257594,
%U A245858 55756633204272,905519956068420,14816352889289380,179362257853420980,1745771827872126600
%N A245858 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 5.
%H A245858 Alois P. Heinz, <a href="/A245858/b245858.txt">Table of n, a(n) for n = 5..400</a>
%F A245858 E.g.f.: 1/(1-Sum_{j>=5} x^j/j!) - 1/(1-Sum_{j>=6} x^j/j!).
%F A245858 a(n) = A245790(n) - A245791(n) = A245732(n,5) - A245732(n,6).
%p A245858 b:= proc(n, k) option remember; `if`(n=0, 1,
%p A245858       add(b(n-j, k)*binomial(n, j), j=k..n))
%p A245858     end:
%p A245858 a:= n-> b(n, 5) -b(n, 6):
%p A245858 seq(a(n), n=5..30);
%Y A245858 Column k=5 of A245733.
%Y A245858 Cf. A245790, A245791, A245732.
%K A245858 nonn
%O A245858 5,6
%A A245858 _Alois P. Heinz_, Aug 04 2014