A128667 Primes p such that p^2 divides 13^(p-1) - 1.

2, 863, 1747591

Offset

1,1

Comments

No further terms up to 3.127*10^13.

Links

Table of n, a(n) for n=1..3.

Amir Akbary and Sahar Siavashi, The Largest Known Wieferich Numbers, INTEGERS, 18(2018), A3. See Table 1 p. 5.

C. K. Caldwell, Fermat quotient

Richard Fischer, Fermat quotients B^(P-1) == 1 (mod P^2)

Mathematica

Select[Prime[Range[5*10^7]], Mod[ 13^(# - 1) - 1, #^2] == 0 &] (* G. C. Greubel, Jan 18 2018 *)

Crossrefs

Cf. A001220, A014127, A123692, A123693, A128668, A090968, A128669, A039951

Sequence in context: A145748 A141185 A257660 * A199947 A230569 A239149

Adjacent sequences: A128664 A128665 A128666 * A128668 A128669 A128670

Keyword

bref,hard,more,nonn

Author

Alexander Adamchuk, Mar 26 2007

Status

approved