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A187113
Primes of the form abcdabcd..abcda.
1
10061, 10091, 10111, 10141, 10151, 10181, 10211, 10271, 10301, 10321, 10331, 10391, 10501, 10531, 10601, 10631, 10651, 10691, 10711, 10771, 10781, 10831, 10861, 10891, 11071, 11131, 11161, 11171, 11251, 11261, 11311, 11321, 11351, 11411, 11471, 11491, 11551
OFFSET
1,1
COMMENTS
The sequence appears to be infinite. The number of terms below 10^1000 are 5749.
LINKS
EXAMPLE
a(2)= 10091 is in the sequence because it is a prime of the form abcda.
MATHEMATICA
s[n_]:=Select[Union@Flatten@Table[FromDigits@Flatten@Join[IntegerDigits@Table[b, {n}], {IntegerDigits@Floor[b/1000]}], {b, 1000, 9999}], PrimeQ]; Array[s, 2]//Flatten
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Shyam Sunder Gupta, Aug 30 2013
STATUS
approved