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A357029
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E.g.f. satisfies A(x) = 1/(1 - x * A(x))^(log(1 - x * A(x))^2).
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4
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1, 0, 0, 6, 36, 210, 3870, 70224, 1122072, 23086344, 586910880, 15469437456, 441107126856, 14206113541152, 496333927370736, 18463733657766144, 739328759822848320, 31759148433997889280, 1447876893211813379520, 69881726567495477445120
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OFFSET
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0,4
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LINKS
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FORMULA
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E.g.f. satisfies log(A(x)) = -log(1 - x * A(x))^3.
a(n) = Sum_{k=0..floor(n/3)} (3*k)! * (n+1)^(k-1) * |Stirling1(n,3*k)|/k!.
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MATHEMATICA
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m = 20; (* number of terms *)
A[_] = 0;
Do[A[x_] = 1/(1 - x*A[x])^(Log[1 - x*A[x]]^2) + O[x]^m // Normal, {m}];
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PROG
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(PARI) a(n) = sum(k=0, n\3, (3*k)!*(n+1)^(k-1)*abs(stirling(n, 3*k, 1))/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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