a(n) = n^(n+2)*(n+2)^n.A051490a(n) = n^(n+2)*(n+2)^n.Terms a(0) =0a(1) =3a(2) =256a(3) =30375a(4) =5308416a(5) =1313046875a(6) =440301256704External referencesoeis: A051490