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

A357508

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

Terms

    a(0) =-1a(1) =-2a(2) =14a(3) =484a(4) =9230a(5) =153748a(6) =2434964a(7) =37748520a(8) =580043790a(9) =8886848740a(10) =136151207764

External references