a(n) = n^(n+1)*(n+1)^n.A051443a(n) = n^(n+1)*(n+1)^n.Terms a(0) =0a(1) =2a(2) =72a(3) =5184a(4) =640000a(5) =121500000a(6) =32934190464External referencesoeis: A051443