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A057814
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Number of partitions of an n-set into blocks of size > 4.
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14
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1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 127, 463, 1255, 3004, 6722, 140570, 1039260, 5371627, 23202077, 90048525, 814737785, 7967774337, 62895570839, 417560407223, 2455461090505, 18440499041402, 179627278800426, 1770970802250146
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OFFSET
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0,11
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LINKS
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FORMULA
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E.g.f.: exp(exp(x)-1-x-x^2/2-x^3/6-x^4/24).
a(0) = 1; a(n) = Sum_{k=5..n} binomial(n-1,k-1) * a(n-k). - Ilya Gutkovskiy, Feb 09 2020
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MAPLE
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G:={P=Set(Set(Atom, card>=5))}:combstruct[gfsolve](G, labeled, x):seq(combstruct[count]([P, G, labeled], size=i), i=0..27); # Zerinvary Lajos, Dec 16 2007
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MATHEMATICA
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max = 27; CoefficientList[ Series[ Exp[ Exp[x] - Normal[ Series[ Exp[x], {x, 0, 4}]]], {x, 0, max}], x]*Range[0, max]!(* Jean-François Alcover, Apr 25 2012, from e.g.f. *)
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CROSSREFS
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Steven C. Fairgrieve (fsteven(AT)math.wvu.edu), Nov 06 2000
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STATUS
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approved
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