A366176 - OEIS

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A366176

G.f. A(x) satisfies A(x) = 1 + x*A(x)^3/(1 - x)^2.

1, 1, 5, 27, 161, 1030, 6921, 48190, 344669, 2517303, 18695908, 140771477, 1072130229, 8244820518, 63931532190, 499308229278, 3924204043333, 31012883225891, 246304580923299, 1964794017165157, 15735626383151876, 126476316316459089, 1019883740031357941

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..22.

FORMULA

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

PROG

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

CROSSREFS

Partial sums give A199475.

Cf. A001764, A213282, A307678.