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A321113
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Number of permutations p of [n] such that in 0p the largest up-jump equals six and no down-jump is larger than 2.
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2
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26, 170, 1078, 6772, 42366, 263548, 1626122, 9993996, 61372356, 376754190, 2312742484, 14199997152, 87223775288, 536072840284, 3296748123732, 20287763348424, 124932460269594, 769857062164974, 4747179317544360, 29291823451184116, 180856995405347960
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OFFSET
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6,1
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LINKS
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MAPLE
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b:= proc(u, o, k) option remember; `if`(u+o=0, 1,
add(b(u-j, o+j-1, k), j=1..min(2, u))+
add(b(u+j-1, o-j, k), j=1..min(k, o)))
end:
a:= n-> (k-> b(0, n, k)-b(0, n, k-1))(6):
seq(a(n), n=6..30);
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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