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A293571
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E.g.f.: exp(x/(1 + x + x^2)).
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4
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1, 1, -1, -5, 25, 41, -1049, 2899, 54545, -610415, -1363409, 92652011, -651996311, -10663181255, 262674487895, -529402905149, -68312606260319, 1136414207246369, 7701376416944095, -584076369474366245, 6461047290787787321, 173442620419212050761
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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.: Product_{k>0} exp(x^(3*k-2)) / exp(x^(3*k-1)).
a(n) = (3-2*n)*a(n-1) - 3*(n-2)*(n-1)*a(n-2) + (5-2*n)*(n-1)*(n-2)*a(n-3) - (n-4)*(n-3)*(n-2)*(n-1)*a(n-4). - Robert Israel, Jul 27 2020
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MAPLE
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f:= gfun:-rectoproc({a(n) = (3-2*n)*a(n-1) - 3*(n-2)*(n-1)*a(n-2) + (5-2*n)*(n-1)*(n-2)*a(n-3)- (n-4)*(n-3)*(n-2)*(n-1)*a(n-4), a(0)=1, a(1)=1, a(2)=-1, a(3)=-5}, a(n), remember):
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PROG
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(PARI) N=66; x='x+O('x^N); Vec(serlaplace(exp(x/(1+x+x^2))))
(PARI) N=66; x='x+O('x^N); Vec(serlaplace(prod(k=1, N, exp(x^(3*k-2)-x^(3*k-1)))))
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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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