a(n) = 2520*(4*n)!/(n!*(n+2)!^3).A361034a(n) = 2520*(4*n)!/(n!*(n+2)!^3).Terms a(0) =315a(1) =280a(2) =3675a(3) =116424a(4) =5885880a(5) =399072960a(6) =33129291195External referencesoeis: A361034