a(n) = Product_{i=1..n} (2*n-i)*(2*n+i).A093434a(n) = Product_{i=1..n} (2*n-i)*(2*n+i).Terms a(0) =3a(1) =180a(2) =30240a(3) =9979200a(4) =5448643200External referencesoeis: A093434