A075597 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).

3, 131, 11311, 3113111, 231131111, 22311311119, 3223113111199, 132231131111993, 11322311311119931, 7113223113111199313, 171132231131111993137, 31711322311311119931373, 3317113223113111199313733

Offset: 1

Author

Amarnath Murthy, Sep 28 2002

Keywords

• base
• nonn

Crossrefs

Cf. A075595, A075596, A075598, A075599, A075600, A075601, A075602.

Programs

Mathematica

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 *)

Extensions

More terms from Sascha Kurz, Jan 20 2003

One more term from David Wasserman, Jan 20 2005