a(n) = (n-1)! * n^n.A369569a(n) = (n-1)! * n^n.Terms a(0) =1a(1) =4a(2) =54a(3) =1536a(4) =75000a(5) =5598720a(6) =592950960a(7) =84557168640External referencesoeis: A369569