%I #4 Dec 12 2020 06:17:23
%S 4486949,4651993,4941649,5571593,11903257,19397501,19841257,19942001,
%T 20610901,21530501,25793893,42969601,44404093,46336949,51509701,
%U 52786493,53740457,54561401,56120257,56904857,63789749,64028593,65497301,65666449,68441957,72582101
%N 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 (PARI) is(n) = forprime(p=1, 17, if(Mod(n, p^2)^(p-1)!=1, return(0))); 1
%Y Cf. A256236. Row 1 of A319064.
%Y 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 nonn
%O 1,1
%A _Felix Fröhlich_, Dec 08 2020