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

Terms

a(0) =1a(1) =0a(2) =80a(3) =970a(4) =9960a(5) =99950a(6) =999940a(7) =9999930a(8) =99999920a(9) =999999910a(10) =9999999900a(11) =99999999890a(12) =999999999880