G.f.: Sum_{n>=0} 2^n * x^n / (1-x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * x^k]^2.
A246538
G.f.: Sum_{n>=0} 2^n * x^n / (1-x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * x^k]^2.
Terms
- a(0) =1a(1) =3a(2) =15a(3) =87a(4) =559a(5) =3807a(6) =26919a(7) =195399a(8) =1445967a(9) =10859967a(10) =82527687a(11) =633165255a(12) =4896345487a(13) =38117454303a(14) =298435452135
External references
- oeis: A246538