A366268 - OEIS

%I #18 Oct 16 2023 04:31:19

%S 1,2,10,90,930,10530,126282,1576410,20268930,266591490,3569991370,

%T 48509238810,667157894050,9269347395490,129908752970890,

%U 1834347364277530,26071297610067970,372683901080814850,5354668071305293450,77286026066830771930

%N G.f. A(x) satisfies A(x) = 1 + x + x*A(x)^5.

%F a(n) = Sum_{k=0..n} binomial(4*k+1,n-k) * binomial(5*k,k)/(4*k+1).

%F a(n) = A366273(n) + A366273(n-1).

%F G.f.: A(x) = 1/B(-x) where B(x) is the g.f. of A366366.

%o (PARI) a(n) = sum(k=0, n, binomial(4*k+1, n-k)*binomial(5*k, k)/(4*k+1));

%Y Cf. A025227, A366266, A366267.

%Y Cf. A366273, A366366.

%K nonn

%O 0,2

%A _Seiichi Manyama_, Oct 06 2023