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 A343763 #10 Apr 30 2021 12:51:48 %S A343763 3,7,79,2731,8191,121369,22366891 %N A343763 Common prime factors of A007663(183)/1093 and A007663(490)/3511. %C A343763 The sequence is complete (cf. Michon). %C A343763 Are these primes necessarily prime factors of A007663(i)/p when p = prime(i) is a Wieferich prime (A001220)? %C A343763 Note the following curious observation: 3 * 7 * 79 * 2731 * 8191 * 121369 * 22366891 = 100743818301219097892181. That number is a repdigit in bases 4 and 64 and undulating in bases 2, 8, 128, 2048 and 8192. Compare that to observations from John Blythe Dobson (cf. Dobson). %H A343763 J. B. Dobson, <a href="https://johnblythedobson.org/mathematics/Wieferich_primes.html">A note on the two known Wieferich primes</a> %H A343763 Gerard P. Michon, <a href="http://www.numericana.com/data/wieferich.htm">Wieferich Primes 1093 and 3511</a> %o A343763 (PARI) fq(n) = (2^(n-1)-1)/n %o A343763 my(x=fq(1093)/1093, y=fq(3511)/3511); forprime(p=1, , if(Mod(x, p)==0 && Mod(y, p)==0, print1(p, ", "))) %Y A343763 Cf. A001220, A007663, A010785, A033619, A172290, A242715. %K A343763 nonn,fini,full %O A343763 1,1 %A A343763 _Felix Fröhlich_, Apr 28 2021