Digit '2' concatenated with a(n) is a lucky number.

Terms

a(0) =1a(1) =5a(2) =11a(3) =19a(4) =23a(5) =31a(6) =35a(7) =37a(8) =41a(9) =59a(10) =61a(11) =67a(12) =73a(13) =83a(14) =85a(15) =89a(16) =97a(17) =113a(18) =115a(19) =121a(20) =125a(21) =127a(22) =133a(23) =163a(24) =173a(25) =187a(26) =209a(27) =211a(28) =215a(29) =217