a(n) = 10^n - n^9.

Terms

a(0) =1a(1) =9a(2) =-412a(3) =-18683a(4) =-252144a(5) =-1853125a(6) =-9077696a(7) =-30353607a(8) =-34217728a(9) =612579511a(10) =9000000000a(11) =97642052309a(12) =994840219648