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%I #4 May 26 2019 15:00:55
%S 361,476,699,977,1121,1145,1293,1667,1745,1868,2157,2382,2468,2665,
%T 2793,2897,3038,3149,3526,4033,4643,4746,4789,5032,5073,5567,5651,
%U 5660,5777,5824,6205,6320,6346,6377,6421,6732,6769,6949,6957,6976,7318,7669,7793,7937
%N Bases b where exactly six primes p with p < b exist such that p is a base-b Wieferich prime.
%C Numbers n such that A255920(n) = 6.
%o (PARI) is(n) = my(i=0); forprime(p=1, n-1, if(Mod(n, p^2)^(p-1)==1, i++)); i==6
%Y Cf. A255920.
%Y Cf. bases b with exactly k base-b Wieferich primes less than b: A255921 (k=0), A255922 (k=1), A255923 (k=2), A255924 (k=3), A255925 (k=4), A325881 (k=5), A325883 (k=7), A325884 (k=8), A325885 (k=9), A325886 (k=10).
%K nonn
%O 1,1
%A _Felix Fröhlich_, May 26 2019
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