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A245859
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Number of preferential arrangements of n labeled elements such that the minimal number of elements per rank equals 6.
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2
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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
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OFFSET
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6,7
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LINKS
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Alois P. Heinz, Table of n, a(n) for n = 6..400
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FORMULA
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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).
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MAPLE
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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);
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CROSSREFS
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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
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KEYWORD
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nonn
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AUTHOR
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Alois P. Heinz, Aug 04 2014
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STATUS
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approved
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