cp's OEIS Frontend

A245859 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 6.

%I A245859 #6 Aug 04 2014 13:05:23
%S A245859 1,0,0,0,0,0,924,3432,6006,10010,16016,24752,17190264,139729800,
%T A245859 748339320,2910015528,9794896188,30251595066,2396910064472,
%U A245859 33228482071400,291616291666700,2036218597884900,11895959650285620,61536913327513260,1662981928016982300
%N A245859 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 6.
%H A245859 Alois P. Heinz, <a href="/A245859/b245859.txt">Table of n, a(n) for n = 6..400</a>
%F A245859 E.g.f.: 1/(1-Sum_{j>=6} x^j/j!) - 1/(1-Sum_{j>=7} x^j/j!).
%F A245859 a(n) = A245791(n) - A245792(n) = A245732(n,6) - A245732(n,7).
%p A245859 b:= proc(n, k) option remember; `if`(n=0, 1,
%p A245859       add(b(n-j, k)*binomial(n, j), j=k..n))
%p A245859     end:
%p A245859 a:= n-> b(n, 6) -b(n, 7):
%p A245859 seq(a(n), n=6..35);
%Y A245859 Column k=6 of A245733.
%Y A245859 a(n) = A245791, A245792, A245732.
%K A245859 nonn
%O A245859 6,7
%A A245859 _Alois P. Heinz_, Aug 04 2014