A325881 Bases b where exactly five primes p with p < b exist such that p is a base-b Wieferich prime.

99, 161, 226, 293, 313, 424, 521, 557, 577, 606, 632, 649, 753, 757, 821, 874, 901, 925, 937, 1030, 1033, 1081, 1108, 1116, 1149, 1342, 1443, 1457, 1524, 1549, 1557, 1586, 1618, 1668, 1777, 1921, 1927, 1929, 1993, 2039, 2060, 2061, 2069, 2077, 2098, 2141, 2269

Offset

1,1

Comments

Numbers n such that A255920(n) = 5.

Links

Table of n, a(n) for n=1..47.

Prog

(PARI) is(n) = my(i=0); forprime(p=1, n-1, if(Mod(n, p^2)^(p-1)==1, i++)); i==5

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), A325882 (k=6), A325883 (k=7), A325884 (k=8), A325885 (k=9), A325886 (k=10).

Sequence in context: A165603 A095420 A064112 * A185498 A126230 A055164

Adjacent sequences: A325878 A325879 A325880 * A325882 A325883 A325884

Keyword

nonn

Author

Felix Fröhlich, May 26 2019

Status

approved