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

A037964

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

Terms

    a(0) =0a(1) =4a(2) =32a(3) =472a(4) =6400a(5) =92504a(6) =1351616a(7) =20060016a(8) =300533760a(9) =4537591960a(10) =68923172032

External references