A378151 - OEIS

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A378151

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

1, 0, 0, 1, 3, 3, 4, 18, 45, 72, 153, 450, 1066, 2172, 5142, 13381, 31752, 72333, 176475, 441909, 1065528, 2551465, 6292857, 15620439, 38229235, 93698523, 232545105, 578019090, 1430290512, 3548336724, 8851036863, 22092054588, 55093739760, 137681640450

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

OFFSET

0,5

LINKS

Table of n, a(n) for n=0..33.

FORMULA

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

PROG

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

CROSSREFS

Cf. A000045, A256169, A378152.

Cf. A115055, A378153.