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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).
8
3, 131, 11311, 3113111, 231131111, 22311311119, 3223113111199, 132231131111993, 11322311311119931, 7113223113111199313, 171132231131111993137, 31711322311311119931373, 3317113223113111199313733
OFFSET
1,1
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 *)
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