a(n) = (18*n)!*(4*n)!/((12*n)!*(9*n)!*n!).A295443a(n) = (18*n)!*(4*n)!/((12*n)!*(9*n)!*n!).Terms a(0) =1a(1) =884a(2) =1887900a(3) =4549731788External referencesoeis: A295443