a(n) = Sum_{k=0..n} (k*n)^k.A155956a(n) = Sum_{k=0..n} (k*n)^k.Terms a(0) =1a(1) =2a(2) =19a(3) =769a(4) =67333a(5) =9929106a(6) =2201420095a(7) =683765250589External referencesoeis: A155956