A369506 - OEIS

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A369506

Expansion of (1/x) * Series_Reversion( x / ((1+x)^3+x^2)^2 ).

1, 6, 53, 548, 6192, 74074, 922142, 11822082, 155024190, 2069570934, 28033435791, 384329462490, 5322745393480, 74357950874850, 1046564375245893, 14826433687124098, 211251475010201934, 3025331234242178508, 43523061969049245589, 628692982662691174722

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OFFSET

0,2

LINKS

Table of n, a(n) for n=0..19.

Index entries for reversions of series

FORMULA

a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} binomial(2*n+2,k) * binomial(6*n-3*k+6,n-2*k).

PROG

(PARI) my(N=30, x='x+O('x^N)); Vec(serreverse(x/((1+x)^3+x^2)^2)/x)

(PARI) a(n) = sum(k=0, n\2, binomial(2*n+2, k)*binomial(6*n-3*k+6, n-2*k))/(n+1);

CROSSREFS

Cf. A143927, A369503.

Sequence in context: A055973 A223345 A362907 * A066357 A276365 A185148

Adjacent sequences: A369503 A369504 A369505 * A369507 A369508 A369509

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Jan 25 2024

STATUS

approved