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A126787
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G.f.: B(x)*B(2!*x^2)*B(3!*x^3)*..., where B(x) is g.f. of A000142.
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2
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1, 1, 4, 14, 66, 308, 1888, 12240, 95640, 827904, 8106960, 87387264, 1035645312, 13316300928, 184988692800, 2756878875648, 43888205438208, 742943286892800, 13326434312808960, 252448071959572992, 5036116692383428608, 105523926692032447488
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OFFSET
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0,3
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COMMENTS
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Take each Ferrers diagram of the partitions of n, label(linearly order) the dots within each row, then linearly order any of the rows that are of equal length. [From Geoffrey Critzer, Mar 21 2009]
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LINKS
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Alois P. Heinz, Table of n, a(n) for n = 0..175
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MAPLE
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B:= proc(n) option remember; local x; unapply (`if`(n<=0, 1, B(n-1)(x)+ n! *x^n), x) end: BB:= proc(n) local x, d; unapply (convert (series (mul (B (floor (n/d))(d!*x^d), d=1..n), x, n+1), polynom), x) end: a:= n-> coeff (BB(n)(x), x, n): seq (a(n), n=0..25); # Alois P. Heinz, Sep 25 2008
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MATHEMATICA
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CoefficientList[Series[Product[Sum[x^(n*k) n!^k*k!, {k, 0, 20}], {n, 1, 20}], {x, 0, 20}], x] [From Geoffrey Critzer, Mar 21 2009]
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CROSSREFS
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Cf. A096161, A110143.
Sequence in context: A020041 A081891 A119857 * A187742 A129219 A007025
Adjacent sequences: A126784 A126785 A126786 * A126788 A126789 A126790
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic, Feb 18 2007
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EXTENSIONS
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More terms from Alois P. Heinz, Sep 25 2008
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STATUS
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approved
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