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 A128667 #20 Apr 22 2025 12:19:07 %S A128667 2,863,1747591 %N A128667 Primes p such that p^2 divides 13^(p-1) - 1. %C A128667 No further terms up to 3.127*10^13. %D A128667 Paulo Ribenboim, The Little Book of Bigger Primes, Springer-Verlag NY 2004. See p. 233. %H A128667 Amir Akbary and Sahar Siavashi, <a href="http://math.colgate.edu/~integers/s3/s3.Abstract.html">The Largest Known Wieferich Numbers</a>, INTEGERS, 18(2018), A3. See Table 1 p. 5. %H A128667 C. K. Caldwell, <a href="https://t5k.org/glossary/xpage/FermatQuotient.html">Fermat quotient</a> %H A128667 Richard Fischer, <a href="http://www.fermatquotient.com/FermatQuotienten/">Fermat quotients B^(P-1) == 1 (mod P^2)</a> %t A128667 Select[Prime[Range[5*10^7]], Mod[ 13^(# - 1) - 1, #^2] == 0 &] (* _G. C. Greubel_, Jan 18 2018 *) %Y A128667 Cf. A001220, A014127, A123692, A123693, A128668, A090968, A128669, A039951 %K A128667 bref,hard,more,nonn %O A128667 1,1 %A A128667 _Alexander Adamchuk_, Mar 26 2007