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A369505
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Expansion of (1/x) * Series_Reversion( x / ((1+x)^3+x)^2 ).
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1
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1, 8, 86, 1066, 14361, 204314, 3020745, 45955442, 714723588, 11312450432, 181625888244, 2950848879096, 48423670556100, 801454908292020, 13363137183238881, 224253208102065664, 3784736105491395780, 64197997357038408976, 1093863031541592651003
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (1/(n+1)) * Sum_{k=0..n} binomial(2*n+2,k) * binomial(6*n-3*k+6,n-k).
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PROG
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(PARI) my(N=20, x='x+O('x^N)); Vec(serreverse(x/((1+x)^3+x)^2)/x)
(PARI) a(n) = sum(k=0, n, binomial(2*n+2, k)*binomial(6*n-3*k+6, n-k))/(n+1);
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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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