All 81 combinations of prefixing and following a(n) by a single digit are nonprime.

Terms

a(0) =2437a(1) =5620a(2) =7358a(3) =11111a(4) =13308a(5) =13332a(6) =13650a(7) =14612a(8) =19737a(9) =19817a(10) =24217a(11) =25213a(12) =26302a(13) =27971a(14) =28472a(15) =28838a(16) =29289a(17) =29542a(18) =29650a(19) =31328a(20) =33027a(21) =33170a(22) =35914a(23) =35970a(24) =36186a(25) =37977a(26) =38327a(27) =39127a(28) =39608a(29) =40078