%I #10 Aug 04 2024 10:15:08

%S 1,6,27,144,648,3564,15066,91368,325863,2519910,5487183,80131680,

%T -19315584,3165288840,-10368295812,157258666944,-910416537216,

%U 9230359934844,-66824394346314,594882273889656,-4709265051598938,40223940845756976,-330361209519974280

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

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

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

%Y Cf. A001019, A373713.

%K sign

%O 0,2

%A _Seiichi Manyama_, Aug 04 2024