A127106 Numbers k such that k^2 divides 6^k-1.

1, 5, 1555, 9673655, 187159211791705, 776119592182705

Offset: 1

Author

Alexander Adamchuk, Jan 05 2007

Keywords

• hard
• more
• nonn

Comments

Subsequence of A014946.

Crossrefs

Cf. A127100, A127101, A127102, A127103, A127104, A127105, A127107, A127092, A014946.

Programs

Mathematica

Select[Range[20000], IntegerQ[(PowerMod[6, #, #^2 ]-1)/#^2 ]&]

Extensions

Two more terms from Max Alekseyev, May 05 2010