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 A339536 #4 Dec 12 2020 06:17:23 %S A339536 4486949,4651993,4941649,5571593,11903257,19397501,19841257,19942001, %T A339536 20610901,21530501,25793893,42969601,44404093,46336949,51509701, %U A339536 52786493,53740457,54561401,56120257,56904857,63789749,64028593,65497301,65666449,68441957,72582101 %N A339536 Numbers b > 1 such that the smallest seven primes, i.e., 2, 3, 5, 7, 11, 13 and 17 are base-b Wieferich primes. %o A339536 (PARI) is(n) = forprime(p=1, 17, if(Mod(n, p^2)^(p-1)!=1, return(0))); 1 %Y A339536 Cf. A256236. Row 1 of A319064. %Y A339536 Cf. smallest k primes are base-b Wieferich primes: A339531 (k=2), A339532 (k=3), A339533 (k=4), A339534 (k=5), A339535 (k=6), A339537 (k=8). %K A339536 nonn %O A339536 1,1 %A A339536 _Felix Fröhlich_, Dec 08 2020