A364595 - OEIS

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A364595

G.f. satisfies A(x) = 1/(1-x) + x^3*(1-x)*A(x)^3.

2

1, 1, 1, 2, 3, 4, 8, 15, 25, 50, 102, 193, 390, 815, 1645, 3385, 7141, 14893, 31196, 66309, 140752, 299043, 640367, 1373929, 2950006, 6360976, 13749865, 29753891, 64547097, 140329453, 305470485, 666084272, 1454920255, 3181946080, 6968134645, 15280422274

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..35.

FORMULA

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

PROG

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

CROSSREFS

Cf. A364596, A364597.

Sequence in context: A097029 A122774 A274166 * A352817 A189740 A118841

Adjacent sequences: A364592 A364593 A364594 * A364596 A364597 A364598

KEYWORD

nonn,easy

AUTHOR

Seiichi Manyama, Jul 29 2023

STATUS

approved