a(n) = n^n * (n^2 - 1)/24.A060348a(n) = n^n * (n^2 - 1)/24.Terms a(0) =9a(1) =160a(2) =3125a(3) =68040a(4) =1647086a(5) =44040192a(6) =1291401630a(7) =41250000000External referencesoeis: A060348