

A232066


Periodic primes: primes p whose decimal expansion can be written as sss...st, where s is nonempty string of digits not beginning with 0, there are at least two copies of s, and t (which may be absent) is a prefix of s.


2



11, 18181, 32323, 35353, 72727, 74747, 78787, 94949, 95959, 1041041, 1051051, 1131131, 1191191, 1201201, 1212121, 1221221, 1231231, 1261261, 1281281, 1311311, 1381381, 1401401, 1411411, 1491491, 1501501, 1551551, 1581581, 1616161, 1621621, 1641641, 1671671
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OFFSET

1,1


COMMENTS

The terms > 10^4 in A032758 appear in this sequence.
The terms > 10^20 in A231588 appear in this sequence.


LINKS

Paul Tek, Table of n, a(n) for n = 1..5972
Paul Tek, PARI program for this sequence


EXAMPLE

9779779 = 9779779,
727272727 = 727272727 = 727272727.


PROG

(PARI) See Link section.


CROSSREFS

Cf. A032758, A231588.
A004022 is a subsequence (these are the terms where s=1 and t is absent).  Harvey P. Dale, Jul 09 2019
Sequence in context: A199148 A248732 A252862 * A330301 A264917 A198668
Adjacent sequences: A232063 A232064 A232065 * A232067 A232068 A232069


KEYWORD

base,nonn


AUTHOR

Paul Tek, Nov 17 2013


EXTENSIONS

Definition corrected by N. J. A. Sloane, Jul 09 2019


STATUS

approved



