a(n) = (1/16)*( binomial(4*n, 2*n) - (-1)^n*binomial(2*n, n) + (1-(-1)^n)*binomial(2*n, n)^2 ).

A037980

a(n) = (1/16)*( binomial(4*n, 2*n) - (-1)^n*binomial(2*n, n) + (1-(-1)^n)*binomial(2*n, n)^2 ).

Terms

    a(0) =0a(1) =1a(2) =4a(3) =109a(4) =800a(5) =19501a(6) =168952a(7) =3979830a(8) =37566720a(9) =862687045a(10) =8615396504a(11) =193710517650

External references