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A178900 First nonzero value of a^(p-1) - 1 mod p^2, for a > 0 coprime to the n-th Wieferich prime p. 2
341016, 24577 (list; graph; refs; listen; history; text; internal format)
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

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

A. Ostafe and I. Shparlinski (2010), Pseudorandomness and Dynamics of Fermat Quotients

FORMULA

a(n) = A178815(A000720(p))^(p-1) - 1 mod p^2, where p = A001220(n).

a(n) mod p = A178844(A000720(p)), where p = A001220(n).

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

Cf. A001220, A178815, A178844.

Sequence in context: A182132 A182515 A236703 * A159462 A151559 A151563

Adjacent sequences:  A178897 A178898 A178899 * A178901 A178902 A178903

KEYWORD

bref,hard,more,nonn

AUTHOR

Jonathan Sondow, Jun 23 2010

STATUS

approved

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Last modified October 14 07:31 EDT 2019. Contains 327995 sequences. (Running on oeis4.)