

A178812


(2^(p1)  1)/p^2 modulo prime p, if p^2 divides 2^(p1)  1.


2




OFFSET

1,1


COMMENTS

(2^(p1)  1)/p^2 modulo p, where p is a Wieferich prime A001220.
(2^(p1)  1)/p^2 modulo p, if prime p divides the Fermat quotient (2^(p1)  1)/p.
See A001220 for references, links, and additional comments.


LINKS

Table of n, a(n) for n=1..2.


FORMULA

a(n) = (2^(p1)  1)/p^2 modulo p, where p = A001220(n).
a(1) = A178813(1).


EXAMPLE

a(1) = 487 as the first Wieferich prime is 1093 and (2^1092  1)/1093^2 == 487 (mod 1093).
The 2nd Wieferich prime is 3511 and (2^3510  1)/3511^2 == 51 (mod 3511), so a(2) = 51.


CROSSREFS

Cf. A001220, A178813.
Sequence in context: A252076 A178813 A178814 * A124667 A142540 A048424
Adjacent sequences: A178809 A178810 A178811 * A178813 A178814 A178815


KEYWORD

bref,hard,more,nonn


AUTHOR

Jonathan Sondow, Jun 16 2010


STATUS

approved



