A379039 G.f. A(x) satisfies A(x) = ( (1 + x) * (1 + x*A(x)^2) )^2.

1, 4, 22, 172, 1513, 14356, 143228, 1480956, 15728516, 170558634, 1880568650, 21019304814, 237615558790, 2712066792304, 31210387143556, 361738488066632, 4218907281330372, 49476183230651216, 583066018329260673, 6901459436855306662, 82011678696864842013

Offset

0,2

Links

Table of n, a(n) for n=0..20.

Formula

G.f.: A(x) = B(x)^2 where B(x) is the g.f. of A364337.

a(n) = Sum_{k=0..n} binomial(4*k+2,k) * binomial(4*k+2,n-k)/(2*k+1).

Prog

(PARI) a(n) = sum(k=0, n, binomial(4*k+2, k)*binomial(4*k+2, n-k)/(2*k+1));

Crossrefs

Cf. A004798, A073155, A379037.

Cf. A364337, A379038.

Sequence in context: A350268 A353186 A346665 * A340332 A207654 A197923

Adjacent sequences: A379036 A379037 A379038 * A379040 A379041 A379042

Keyword

nonn

Author

Seiichi Manyama, Dec 14 2024

Status

approved