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%I #6 Dec 12 2020 06:17:06
%S 19601,22049,48149,52057,67357,84457,85193,93493,104057,113257,115757,
%T 132857,160849,171793,186101,198449,206749,209249,224549,228457,
%U 235493,261593,265501,280801,297901,317501,326701,329201,329849,346301,359857,374293,374849
%N Numbers b > 1 such that the smallest five primes, i.e., 2, 3, 5, 7 and 11 are base-b Wieferich primes.
%t Select[Range[2, 375000], Function[b, AllTrue[{2, 3, 5, 7, 11}, PowerMod[b, (# - 1), #^2] == 1 &]]] (* _Michael De Vlieger_, Dec 10 2020 *)
%o (PARI) is(n) = forprime(p=1, 11, if(Mod(n, p^2)^(p-1)!=1, return(0))); 1
%Y Cf. A256236. Row 1 of A319062.
%Y Cf. smallest k primes are base-b Wieferich primes: A339531 (k=2), A339532 (k=3), A339533 (k=4), A339535 (k=6), A339536 (k=7), A339537 (k=8).
%K nonn
%O 1,1
%A _Felix Fröhlich_, Dec 08 2020
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