G.f.: Sum_{n>=0} x^n / (1+x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * x^k] * [Sum_{k=0..n} C(n,k)^2 * (-x)^k].

A249891

G.f.: Sum_{n>=0} x^n / (1+x)^(2*n+1) * [Sum_{k=0..n} C(n,k)^2 * x^k] * [Sum_{k=0..n} C(n,k)^2 * (-x)^k].

Terms

    a(0) =1a(1) =-1a(2) =-11a(3) =59a(4) =241a(5) =-3361a(6) =-419a(7) =172451a(8) =-575399a(9) =-7443481a(10) =58900909a(11) =216416771a(12) =-4229184959a(13) =2577683471a(14) =244556409709

External references