

A102498


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


4



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
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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.
Sequence in context: A298235 A111676 A058030 * A019399 A255581 A061967
Adjacent sequences: A102495 A102496 A102497 * A102499 A102500 A102501


KEYWORD

easy,nonn,base


AUTHOR

Mark Hudson (mrmarkhudson(AT)hotmail.com), Jan 13 2005


STATUS

approved



