Numbers k such that k surrounded by digit '3' is a prime.

Terms

a(0) =1a(1) =5a(2) =7a(3) =8a(4) =16a(5) =20a(6) =25a(7) =31a(8) =32a(9) =34a(10) =37a(11) =41a(12) =43a(13) =46a(14) =53a(15) =58a(16) =59a(17) =61a(18) =62a(19) =64a(20) =67a(21) =73a(22) =79a(23) =80a(24) =82a(25) =83a(26) =85a(27) =86a(28) =92a(29) =94