A339534 Numbers b > 1 such that the smallest five primes, i.e., 2, 3, 5, 7 and 11 are base-b Wieferich primes.

19601, 22049, 48149, 52057, 67357, 84457, 85193, 93493, 104057, 113257, 115757, 132857, 160849, 171793, 186101, 198449, 206749, 209249, 224549, 228457, 235493, 261593, 265501, 280801, 297901, 317501, 326701, 329201, 329849, 346301, 359857, 374293, 374849

Offset

1,1

Links

Table of n, a(n) for n=1..33.

Mathematica

Select[Range[2, 375000], Function[b, AllTrue[{2, 3, 5, 7, 11}, PowerMod[b, (# - 1), #^2] == 1 &]]] (* Michael De Vlieger, Dec 10 2020 *)

Prog

(PARI) is(n) = forprime(p=1, 11, if(Mod(n, p^2)^(p-1)!=1, return(0))); 1

Crossrefs

Cf. A256236. Row 1 of A319062.

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).

Sequence in context: A022213 A093219 A184493 * A319062 A344829 A221333

Adjacent sequences: A339531 A339532 A339533 * A339535 A339536 A339537

Keyword

nonn

Author

Felix Fröhlich, Dec 08 2020

Status

approved