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A362322
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a(n) = n! * Sum_{k=0..floor(n/4)} (-n)^k / (k! * (n-4*k)!).
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2
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1, 1, 1, 1, -95, -599, -2159, -5879, 1276801, 14669425, 90669601, 402407281, -136515598559, -2275742812199, -19922903656655, -122565283331399, 56538094207096321, 1235380139032068961, 13993348375743336001, 110062069784059565665
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OFFSET
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0,5
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LINKS
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FORMULA
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a(n) = n! * [x^n] exp(x - n*x^4).
E.g.f.: exp( ( LambertW(4*x^4)/4 )^(1/4) ) / (1 + LambertW(4*x^4)).
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PROG
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(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(exp((lambertw(4*x^4)/4)^(1/4))/(1+lambertw(4*x^4))))
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CROSSREFS
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KEYWORD
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sign
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AUTHOR
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STATUS
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approved
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