Numbers k such that k concatenated with itself is a lucky number.

Terms

a(0) =3a(1) =9a(2) =21a(3) =23a(4) =51a(5) =59a(6) =63a(7) =71a(8) =75a(9) =87a(10) =89a(11) =99a(12) =105a(13) =111a(14) =117a(15) =123a(16) =129a(17) =135a(18) =143a(19) =147a(20) =153a(21) =171a(22) =173a(23) =177a(24) =191a(25) =201a(26) =237a(27) =243a(28) =255a(29) =263