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 A280150 #17 Aug 07 2019 13:02:00 %S A280150 5,7,19,113,2741 %N A280150 Primes p such that 68^(p-1) == 1 (mod p^2). %C A280150 For p = 5 and 113 is 68^(p-1) == 1 (mod p^3). %C A280150 No further terms up to 7.74*10^13 (cf. Fischer link). - _Felix Fröhlich_, Dec 27 2016 %H A280150 R. Fischer, <a href="http://www.fermatquotient.com/FermatQuotienten/FermQ_Sort.txt">Thema: Fermatquotient B^(P-1) == 1 (mod P^2)</a> %t A280150 Select[Prime[Range[500]],PowerMod[68,#-1,#^2]==1&] (* _Harvey P. Dale_, Aug 07 2019 *) %o A280150 (PARI) forprime(p=1, , if(Mod(68, p^2)^(p-1)==1, print1(p, ", "))) \\ _Felix Fröhlich_, Dec 27 2016 %Y A280150 Cf. A001220, A273085. %K A280150 nonn,more %O A280150 1,1 %A A280150 _Thomas Ordowski_, Dec 27 2016 %E A280150 a(5) from _Felix Fröhlich_, Dec 27 2016