Palindromic Kaprekar numbers.

Terms

a(0) =1a(1) =9a(2) =55a(3) =99a(4) =999a(5) =7777a(6) =9999a(7) =22222a(8) =99999a(9) =999999a(10) =4444444a(11) =9999999a(12) =88888888a(13) =99999999a(14) =909090909a(15) =999999999a(16) =1111111111a(17) =9999999999a(18) =55555555555a(19) =99999999999a(20) =999999999999