A367059 - OEIS

A367059

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

1, 1, 3, 13, 61, 309, 1651, 9153, 52161, 303681, 1798459, 10800237, 65614237, 402544597, 2490398139, 15519350593, 97326638145, 613786324353, 3890080513395, 24764386415821, 158281551244029, 1015314894877237, 6534249237530115, 42178452056044929

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

OFFSET

0,3

LINKS

Table of n, a(n) for n=0..23.

FORMULA

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

PROG

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

CROSSREFS

Cf. A366676, A367057, A367058, A367060, A367061, A367062.

Sequence in context: A256333 A200215 A074548 * A243014 A258799 A375651

Adjacent sequences: A367056 A367057 A367058 * A367060 A367061 A367062

KEYWORD

nonn

AUTHOR

Seiichi Manyama, Nov 04 2023

STATUS

approved