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A245859 Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 6. 2
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 (list; graph; refs; listen; history; text; internal format)
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 A177304

Adjacent sequences: A245856 A245857 A245858 * A245860 A245861 A245862

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Aug 04 2014

STATUS

approved

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Last modified February 3 21:17 EST 2023. Contains 360045 sequences. (Running on oeis4.)