a(n) = 10^n - n^11.

Terms

a(0) =1a(1) =9a(2) =-1948a(3) =-176147a(4) =-4184304a(5) =-48728125a(6) =-361797056a(7) =-1967326743a(8) =-8489934592a(9) =-30381059609a(10) =-90000000000a(11) =-185311670611a(12) =256991629312