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 A339533 #6 Dec 12 2020 06:16:57
%S A339533 557,901,1549,2449,4049,5293,5849,6193,7057,7957,8801,9701,12349,
%T A339533 13249,14093,14993,15857,16201,16757,18001,19601,20501,21149,21493,
%U A339533 22049,23257,23293,24893,25057,25793,26657,27557,28549,30349,31949,32849,33301,34201,35801
%N A339533 Numbers b > 1 such that the smallest four primes, i.e., 2, 3, 5 and 7 are base-b Wieferich primes.
%t A339533 Select[Range[2, 36000], Function[b, AllTrue[{2, 3, 5, 7}, PowerMod[b, (# - 1), #^2] == 1 &]]] (* _Michael De Vlieger_, Dec 10 2020 *)
%o A339533 (PARI) is(n) = forprime(p=1, 7, if(Mod(n, p^2)^(p-1)!=1, return(0))); 1
%Y A339533 Cf. A256236. Row 1 of A319061.
%Y A339533 Cf. smallest k primes are base-b Wieferich primes: A339531 (k=2), A339532 (k=3), A339534 (k=5), A339535 (k=6), A339536 (k=7), A339537 (k=8).
%K A339533 nonn
%O A339533 1,1
%A A339533 _Felix Fröhlich_, Dec 08 2020