A102498 - OEIS

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A102498

Values of n for which the concatenation 3nn3 (from sequence A100896) are primes.

13, 23, 28, 29, 38, 43, 49, 50, 52, 56, 64, 67, 80, 83, 92, 94, 95, 97, 1000, 1003, 1024, 1025, 1028, 1039, 1046, 1048, 1051, 1058, 1063, 1072, 1073, 1075, 1084, 1087, 1091, 1096, 1103, 1109, 1114, 1117, 1130, 1136, 1145, 1154, 1168, 1189, 1192

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 0..1000

EXAMPLE

The number 313133 is prime and corresponds to n=13.

The number 3100010003 is prime and corresponds to n=1000.

MATHEMATICA

Select[Range[1200], PrimeQ[FromDigits[Join[{3}, IntegerDigits[#], IntegerDigits[ #], {3}]]]&] (* Harvey P. Dale, Dec 24 2012 *)

CROSSREFS

The full sequence of integers of the form 3nn3 is A100896. The primes the correspond to these values of n are sequence A102499.