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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
OFFSET
1,1
COMMENTS
The terms > 10^4 in A032758 appear in this sequence.
The terms > 10^20 in A231588 appear in this sequence.
EXAMPLE
9779779 = 977|977|9,
727272727 = 72|72|72|72|7 = 7272|7272|7.
PROG
(PARI) See Link section.
CROSSREFS
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
KEYWORD
base,nonn
AUTHOR
Paul Tek, Nov 17 2013
EXTENSIONS
Definition corrected by N. J. A. Sloane, Jul 09 2019
STATUS
approved