Digit '2' concatenated with a(n) is a prime.

Terms

a(0) =3a(1) =9a(2) =11a(3) =23a(4) =27a(5) =29a(6) =33a(7) =39a(8) =41a(9) =51a(10) =57a(11) =63a(12) =69a(13) =71a(14) =77a(15) =81a(16) =83a(17) =93a(18) =111a(19) =113a(20) =129a(21) =131a(22) =137a(23) =141a(24) =143a(25) =153a(26) =161a(27) =179a(28) =203a(29) =207