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

1,1

Links

Table of n, a(n) for n=1..13.

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 *)

Crossrefs

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

Sequence in context: A082439 A082622 A332113 * A262639 A082563 A083999

Adjacent sequences: A075594 A075595 A075596 * A075598 A075599 A075600

Keyword

base,nonn

Author

Amarnath Murthy, Sep 28 2002

Extensions

More terms from Sascha Kurz, Jan 20 2003

One more term from David Wasserman, Jan 20 2005

Status

approved