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 A339535 #6 Dec 12 2020 06:17:14
%S A339535 132857,171793,261593,618301,700993,997757,1211201,1365857,1388593,
%T A339535 1542293,1557593,1681649,1692557,1906001,2086793,2124757,2245357,
%U A339535 2293757,2341349,2443501,2822957,3025457,3036401,3435193,3554657,3569257,3814649,4028093,4048901
%N A339535 Numbers b > 1 such that the smallest six primes, i.e., 2, 3, 5, 7, 11 and 13 are base-b Wieferich primes.
%t A339535 Select[Range[2, 4100000], Function[b, AllTrue[{2, 3, 5, 7, 11, 13}, PowerMod[b, (# - 1), #^2] == 1 &]]] (* _Michael De Vlieger_, Dec 10 2020 *)
%o A339535 (PARI) is(n) = forprime(p=1, 13, if(Mod(n, p^2)^(p-1)!=1, return(0))); 1
%Y A339535 Cf. A256236. Row 1 of A319063.
%Y A339535 Cf. smallest k primes are base-b Wieferich primes: A339531 (k=2), A339532 (k=3), A339533 (k=4), A339534 (k=5), A339536 (k=7), A339537 (k=8).
%K A339535 nonn
%O A339535 1,1
%A A339535 _Felix Fröhlich_, Dec 08 2020