A367111 G.f. satisfies A(x) = 1 + x*A(x) + 2*x^3*A(x)^3.

1, 1, 1, 3, 9, 21, 53, 155, 449, 1273, 3721, 11155, 33529, 101245, 309037, 950587, 2936833, 9117169, 28448209, 89134435, 280252585, 884123429, 2797933733, 8879167067, 28249550913, 90091462761, 287946752601, 922194331891, 2959055180953, 9511538457229

Offset

0,4

Links

Table of n, a(n) for n=0..29.

Formula

a(n) = Sum_{k=0..floor(n/3)} 2^k * binomial(n,3*k) * A001764(k).

Prog

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

Crossrefs

Cf. A001764, A071879, A367112, A367113.

Cf. A190590.

Sequence in context: A005254 A272265 A191796 * A372375 A345108 A007056

Adjacent sequences: A367108 A367109 A367110 * A367112 A367113 A367114

Keyword

nonn,easy

Author

Seiichi Manyama, Nov 05 2023

Status

approved