Digit '7' concatenated with a(n) is a lucky number.

Terms

a(0) =3a(1) =5a(2) =9a(3) =17a(4) =23a(5) =27a(6) =29a(7) =35a(8) =39a(9) =41a(10) =45a(11) =69a(12) =77a(13) =81a(14) =87a(15) =101a(16) =111a(17) =129a(18) =135a(19) =153a(20) =167a(21) =171a(22) =173a(23) =183a(24) =191a(25) =195a(26) =197a(27) =207a(28) =215a(29) =231