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A172291 Numbers whose square divide 2^1092-1. 2
3, 7, 13, 1093 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Up to now there exist only two primes p such that p^2 divide 2^(p-1)-1 (these two are Wieferich primes, see A001220).

LINKS

Table of n, a(n) for n=1..4.

EXAMPLE

Contribution from Reinhard Zumkeller, May 14 2010: (Start)

a(1)^2 = 9 = A177855(5);

a(2)^2 = 49 = A177855(14);

a(3)^2 = 169 = A177855(30);

a(4)^2 = 1194649 = A177855(1843). (End)

CROSSREFS

Cf. A001220, A172290, A172292, A172293.

Sequence in context: A154821 A084741 A135623 * A089305 A112618 A058027

Adjacent sequences:  A172288 A172289 A172290 * A172292 A172293 A172294

KEYWORD

fini,nonn,full

AUTHOR

Artur Jasinski, Jan 30 2010

EXTENSIONS

Keyword full added by Reinhard Zumkeller, May 14 2010

STATUS

approved

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Last modified May 31 19:11 EDT 2020. Contains 334748 sequences. (Running on oeis4.)