A172291 Numbers greater than 1 whose square divide 2^1092-1.

3, 7, 13, 1093

Offset

1,1

Comments

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

Links

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

Example

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.

Sequence in context: A353008 A084741 A135623 * A343589 A089305 A112618

Adjacent sequences: A172288 A172289 A172290 * A172292 A172293 A172294

Keyword

nonn,fini,full

Author

Artur Jasinski, Jan 30 2010

Extensions

Keyword full added by Reinhard Zumkeller, May 14 2010

Status

approved