Kaprekar numbers that are the concatenation of two equal numbers.

Terms

a(0) =55a(1) =99a(2) =5050a(3) =7272a(4) =7777a(5) =9999a(6) =500500a(7) =648648a(8) =851851a(9) =999999a(10) =13641364a(11) =24752475a(12) =25252525a(13) =36363636a(14) =50005000a(15) =61116111a(16) =88888888a(17) =99999999a(18) =1111111111a(19) =3888938889a(20) =4132841328a(21) =5000050000a(22) =5243952439a(23) =9756097560a(24) =9999999999a(25) =159341159341a(26) =175676175676a(27) =233415233415