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

3, 7, 13, 1093

Offset: 1

Author

Artur Jasinski, Jan 30 2010

Keywords

• nonn
• fini
• full

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).

Examples

			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.

Extensions

Keyword full added by Reinhard Zumkeller, May 14 2010