%I
%S 557,901,1549,2449,4049,5293,5849,6193,7057,7957,8801,9701,12349,
%T 13249,14093,14993,15857,16201,16757,18001,19601,20501,21149,21493,
%U 22049,23257,23293,24893,25057,25793,26657,27557,28549,30349,31949,32849,33301,34201,35801
%N Numbers b > 1 such that the smallest four primes, i.e., 2, 3, 5 and 7 are baseb Wieferich primes.
%t Select[Range[2, 36000], Function[b, AllTrue[{2, 3, 5, 7}, PowerMod[b, (#  1), #^2] == 1 &]]] (* _Michael De Vlieger_, Dec 10 2020 *)
%o (PARI) is(n) = forprime(p=1, 7, if(Mod(n, p^2)^(p1)!=1, return(0))); 1
%Y Cf. A256236. Row 1 of A319061.
%Y Cf. smallest k primes are baseb Wieferich primes: A339531 (k=2), A339532 (k=3), A339534 (k=5), A339535 (k=6), A339536 (k=7), A339537 (k=8).
%K nonn
%O 1,1
%A _Felix Fröhlich_, Dec 08 2020
