%I #11 Nov 11 2022 11:51:34
%S 3,131,11311,3113111,231131111,22311311119,3223113111199,
%T 132231131111993,11322311311119931,7113223113111199313,
%U 171132231131111993137,31711322311311119931373,3317113223113111199313733
%N a(1) = 3 and then the smallest prime that is obtained by placing digits on both sides of the previous term. Or smallest prime that encompasses a(n-1).
%t NestList[Select[Flatten[Table[FromDigits[Join[{a},IntegerDigits[#],{b}]],{a,9},{b,1,9,2}]],PrimeQ][[1]]&,3,12] (* _Harvey P. Dale_, Nov 11 2022 *)
%Y Cf. A075595, A075596, A075598, A075599, A075600, A075601, A075602.
%K base,nonn
%O 1,1
%A _Amarnath Murthy_, Sep 28 2002
%E More terms from _Sascha Kurz_, Jan 20 2003
%E One more term from _David Wasserman_, Jan 20 2005