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A325883 Bases b where exactly seven primes p with p < b exist such that p is a base-b Wieferich prime. 9
1451, 1482, 3145, 3147, 3277, 3365, 3376, 4339, 4357, 4365, 4393, 4625, 5649, 5850, 7282, 7624, 8641, 8956, 8957, 9149, 9449, 10040, 10093, 10538, 10835, 10889, 12001, 12476, 12907, 13253, 14005, 14027, 14032, 14500, 15029, 15229, 15797, 15857, 16249, 16757 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Numbers n such that A255920(n) = 7.

LINKS

Table of n, a(n) for n=1..40.

PROG

(PARI) is(n) = my(i=0); forprime(p=1, n-1, if(Mod(n, p^2)^(p-1)==1, i++)); i==7

CROSSREFS

Cf. A255920.

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), A325882 (k=6), A325884 (k=8), A325885 (k=9), A325886 (k=10).

Sequence in context: A208486 A242038 A045099 * A237445 A122421 A187992

Adjacent sequences:  A325880 A325881 A325882 * A325884 A325885 A325886

KEYWORD

nonn

AUTHOR

Felix Fröhlich, May 26 2019

STATUS

approved

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Last modified August 1 16:59 EDT 2021. Contains 346400 sequences. (Running on oeis4.)