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A371041
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E.g.f. satisfies A(x) = exp(x^2*A(x)^3) / (1-x).
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0
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1, 1, 4, 30, 348, 5460, 108480, 2609040, 73713360, 2393087760, 87791891040, 3591843726240, 162157925160000, 8007919490450880, 429418816003457280, 24849579630222547200, 1543505958412498080000, 102430107277414595078400, 7232759636684706937612800
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OFFSET
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0,3
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LINKS
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FORMULA
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E.g.f.: (LambertW( -3*x^2/(1-x)^3 ) / (-3*x^2))^(1/3).
a(n) = n! * Sum_{k=0..floor(n/2)} (3*k+1)^(k-1) * binomial(n+k,n-2*k)/k!.
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PROG
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(PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace((lambertw(-3*x^2/(1-x)^3)/(-3*x^2))^(1/3)))
(PARI) a(n) = n!*sum(k=0, n\2, (3*k+1)^(k-1)*binomial(n+k, n-2*k)/k!);
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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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