a(n) = n*n^n - (n-1)*(n-1)^n.

Terms

a(0) =1a(1) =1a(2) =7a(3) =65a(4) =781a(5) =11529a(6) =201811a(7) =4085185a(8) =93864121a(9) =2413042577a(10) =68618940391