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A369599
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Expansion of (1/x) * Series_Reversion( x * (1/(1+x)^2 - x^3) ).
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1
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1, 2, 5, 15, 54, 223, 993, 4580, 21521, 102563, 495318, 2422302, 11979965, 59824535, 301202673, 1527118720, 7789673832, 39947163395, 205835776301, 1065155017623, 5533253267649, 28844759080896, 150846487065730, 791163319140664, 4160593763997122
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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..floor(n/3)} binomial(n+k,k) * binomial(2*n+2*k+2,n-3*k).
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PROG
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(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x*(1/(1+x)^2-x^3))/x)
(PARI) a(n) = sum(k=0, n\3, binomial(n+k, k)*binomial(2*n+2*k+2, n-3*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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