Numbers k such that k*(k-1) is composed of exactly two different decimal digits.

Terms

a(0) =4a(1) =5a(2) =6a(3) =7a(4) =8a(5) =9a(6) =10a(7) =11a(8) =17a(9) =24a(10) =25a(11) =32a(12) =34a(13) =67a(14) =75a(15) =78a(16) =100a(17) =101a(18) =142a(19) =167a(20) =334a(21) =667a(22) =1000a(23) =1001a(24) =1667a(25) =3334a(26) =6667a(27) =10000a(28) =10001a(29) =16667