A373939 Expansion of 1/(2 - 1/(1 - 9*x)^(2/3)).

1, 6, 81, 1116, 15471, 214974, 2990115, 41609376, 579152592, 8062039188, 112233642606, 1562482974384, 21752802921528, 302844316749948, 4216246872393294, 58699445770011312, 817227085779238851, 11377633930294786182, 158402278494943048161, 2205317108305048202244

Offset

0,2

Links

Table of n, a(n) for n=0..19.

Formula

a(n) = 9^n * Sum_{k>=0} (1/2)^(k+1) * binomial(n-1+2*k/3,n).

Prog

(PARI) my(N=20, x='x+O('x^N)); Vec(1/(2-1/(1-9*x)^(2/3)))

Crossrefs

Cf. A001027, A373818.

Sequence in context: A309902 A196909 A197076 * A234872 A064341 A372321

Adjacent sequences: A373936 A373937 A373938 * A373940 A373941 A373942

Keyword

nonn,easy

Author

Seiichi Manyama, Aug 04 2024

Status

approved