a(n) = ((2*n)!/n!)*2^(2*n+1).A052737a(n) = ((2*n)!/n!)*2^(2*n+1).Terms a(0) =0a(1) =2a(2) =16a(3) =384a(4) =15360a(5) =860160a(6) =61931520a(7) =5449973760a(8) =566797271040External referencesoeis: A052737