A373713 Expansion of 1/(2 - (1 + 9*x)^(1/3)).

1, 3, 0, 18, -81, 567, -3888, 28188, -209952, 1600398, -12417786, 97750152, -778646358, 6264403434, -50826308652, 415388851020, -3416382463113, 28254462711543, -234821716366914, 1960141044056202, -16426217919609621, 138140613244558143, -1165452696039219804

Offset: 0

Author

Seiichi Manyama, Aug 04 2024

Keywords

• sign
• easy

Crossrefs

Cf. A001019, A373714.

Programs

PARI

my(N=30, x='x+O('x^N)); Vec(1/(2-(1+9*x)^(1/3)))

Formula

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