This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A226542 #38 Nov 18 2016 02:28:47
%S A226542 11,19,37,43,67,103,131,137,199,239,293,331,397,439,463,521,547,661,
%T A226542 683,727,859,911,991,1033,1093,1171,1291,1301,1543,1549,1951,2053,
%U A226542 2081,2341,2731,2861,3079,3121,3251,3511,3613,3823,4099,4129,4229,4903,5419,6151
%N A226542 Primes p such that p - 1 can be represented as a repdigit number in some base < p which is a power of two.
%C A226542 It is believed that this is a supersequence of A001220 (Wieferich primes).
%H A226542 Arkadiusz Wesolowski, <a href="/A226542/b226542.txt">Table of n, a(n) for n = 1..1000</a>
%H A226542 John Blythe Dobson, <a href="http://library.uwinnipeg.ca/people/Dobson/mathematics/Wieferich_primes.html">A note on the two known Wieferich Primes</a>
%H A226542 Wells Johnson, <a href="http://gdz.sub.uni-goettingen.de/dms/resolveppn/?PPN=GDZPPN002193698">On the nonvanishing of Fermat quotients (mod p)</a>, Journal f. die reine und angewandte Mathematik 292, (1977): 196-200.
%H A226542 Wikipedia, <a href="http://en.wikipedia.org/wiki/Repdigit">Repdigit</a>
%e A226542 103 is in the sequence because it is prime and 102 = 66 (base 16).
%e A226542 463 is in the sequence because it is prime and 462 = ee (base 32).
%e A226542 7 is not in the sequence since 6 = 6 (base 8) and 8 > 7.
%t A226542 lst = {}; r = 13; Do[If[PrimeQ[p] && Length@Union@IntegerDigits[p - 1, 2^b] == 1, AppendTo[lst, p]], {b, 2, r - 1}, {p, 2^b + 1, 2^r - 1, 2}]; Union[lst]
%Y A226542 Cf. A001220, A010785, A048329, A048333, A048340.
%K A226542 nonn,base
%O A226542 1,1
%A A226542 _Arkadiusz Wesolowski_, Jun 10 2013