98888888889domain: NAppears in sequencesNumber of zeros in numbers 1 to 999..9 (n digits).at n=10A033713Least palindromic multiple of concatenation n,n-1,n-2,...3,2,1.at n=9A109929a(1)=10; a(n) = a(n-1)*10 - 1.at n=10A179555