a(n) = 10^(2*n+1) - 10^n - 1.A181965a(n) = 10^(2*n+1) - 10^n - 1.Terms a(0) =8a(1) =989a(2) =99899a(3) =9998999a(4) =999989999a(5) =99999899999External referencesoeis: A181965