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

Author

Seiichi Manyama, Dec 14 2024

Keywords

• nonn

Crossrefs

Cf. A004798, A073155, A379037.

Cf. A364337, A379038.

Programs

PARI

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

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).