cp's OEIS Frontend

A245861 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 8.

%I A245861 #6 Aug 04 2014 13:06:39
%S A245861 1,0,0,0,0,0,0,0,12870,48620,87516,151164,251940,406980,639540,980628,
%T A245861 9466982712,78881427900,432962644400,1733914096200,6029537213700,
%U A245861 19273224716460,58178097911700,168431757261300,100033451495909100,1461521434059544572
%N A245861 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 8.
%H A245861 Alois P. Heinz, <a href="/A245861/b245861.txt">Table of n, a(n) for n = 8..400</a>
%F A245861 E.g.f.: 1/(1-Sum_{j>=8} x^j/j!) - 1/(1-Sum_{j>=9} x^j/j!).
%F A245861 a(n) = A245793(n) - A245794(n) = A245732(n,8) - A245732(n,9).
%p A245861 b:= proc(n, k) option remember; `if`(n=0, 1,
%p A245861       add(b(n-j, k)*binomial(n, j), j=k..n))
%p A245861     end:
%p A245861 a:= n-> b(n, 8) -b(n, 9):
%p A245861 seq(a(n), n=8..35);
%Y A245861 Column k=8 of A245733.
%Y A245861 Cf. A245793, A245794, A245732.
%K A245861 nonn
%O A245861 8,9
%A A245861 _Alois P. Heinz_, Aug 04 2014