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%I #18 Jul 10 2019 23:13:16
%S 11,18181,32323,35353,72727,74747,78787,94949,95959,1041041,1051051,
%T 1131131,1191191,1201201,1212121,1221221,1231231,1261261,1281281,
%U 1311311,1381381,1401401,1411411,1491491,1501501,1551551,1581581,1616161,1621621,1641641,1671671
%N 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.
%C The terms > 10^4 in A032758 appear in this sequence.
%C The terms > 10^20 in A231588 appear in this sequence.
%H Paul Tek, <a href="/A232066/b232066.txt">Table of n, a(n) for n = 1..5972</a>
%H Paul Tek, <a href="/A232066/a232066.txt">PARI program for this sequence</a>
%e 9779779 = 977|977|9,
%e 727272727 = 72|72|72|72|7 = 7272|7272|7.
%o (PARI) See Link section.
%Y Cf. A032758, A231588.
%Y A004022 is a subsequence (these are the terms where s=1 and t is absent). - _Harvey P. Dale_, Jul 09 2019
%K base,nonn
%O 1,1
%A _Paul Tek_, Nov 17 2013
%E Definition corrected by _N. J. A. Sloane_, Jul 09 2019
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