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

1, 0, 0, 0, 0, 0, 924, 3432, 6006, 10010, 16016, 24752, 17190264, 139729800, 748339320, 2910015528, 9794896188, 30251595066, 2396910064472, 33228482071400, 291616291666700, 2036218597884900, 11895959650285620, 61536913327513260, 1662981928016982300

Offset

6,7

Links

Alois P. Heinz, Table of n, a(n) for n = 6..400

Formula

E.g.f.: 1/(1-Sum_{j>=6} x^j/j!) - 1/(1-Sum_{j>=7} x^j/j!).

a(n) = A245791(n) - A245792(n) = A245732(n,6) - A245732(n,7).

Maple

b:= proc(n, k) option remember; `if`(n=0, 1,
      add(b(n-j, k)*binomial(n, j), j=k..n))
    end:
a:= n-> b(n, 6) -b(n, 7):
seq(a(n), n=6..35);

Crossrefs

Column k=6 of A245733.

a(n) = A245791, A245792, A245732.

Sequence in context: A024750 A024758 A347261 * A172224 A283577 A361608

Adjacent sequences: A245856 A245857 A245858 * A245860 A245861 A245862

Keyword

nonn

Author

Alois P. Heinz, Aug 04 2014

Status

approved