|
|
A178900
|
|
First nonzero value of (a^(p-1) - 1) mod p^2, for a > 0 coprime to the n-th Wieferich prime p.
|
|
2
|
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
It is believed that a(n) = (3^(p-1) - 1) mod p^2 for all n, where p = A001220(n).
See additional comments, references, links and cross-references in A001220.
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
The first Wieferich prime is 1093 and a^1092 - 1 mod 1093^2 = 0, 0, 341016 for a = 1, 2, 3, so a(1) = 341016.
|
|
CROSSREFS
|
|
|
KEYWORD
|
bref,hard,more,nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|