A377242 - OEIS

%I #8 Oct 21 2024 08:57:14

%S 1,3,27,207,2052,18549,188487,1822257,18757170,187833654,1950543018,

%T 19946428524,208533115953,2161631202408,22722158457018,

%U 237747753079992,2510341213633218,26444343663932265,280274270573324547,2967476856390453393,31551693369673358214

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

%F a(n) = (-9)^n * Sum_{k=0..n} binomial(-1/3,k) * binomial(n-4*k/3-1,n-k).

%o (PARI) a(n) = (-9)^n*sum(k=0, n, binomial(-1/3, k)*binomial(n-4*k/3-1, n-k));

%Y Cf. A377241.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Oct 21 2024