L.g.f.: Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k^2)*x^k = Sum_{n>=1} a(n)*x^n/n.

A206851

L.g.f.: Sum_{n>=1} x^n/n * Sum_{k=0..n} binomial(n^2, k^2)*x^k = Sum_{n>=1} a(n)*x^n/n.

Terms

    a(0) =1a(1) =3a(2) =7a(3) =15a(4) =231a(5) =2763a(6) =37773a(7) =3347359a(8) =145164760a(9) =15115517783

External references