A055693 Numbers k such that 10^k == -1 (mod k-1).

2, 102, 41310, 102690, 309162, 315150, 1000002, 2488530, 4564350, 12679002, 17166870, 28855610, 35049930, 38982870, 42176490, 43232070, 53288510, 64253070, 104439090, 126446850, 130659210, 144379602, 208313490, 252852390, 284335410, 284397750, 337122750, 379257930, 385659630

Offset: 1

Author

Robert G. Wilson v, Jun 09 2000

Keywords

• nonn

Programs

Mathematica

Do[If[PowerMod[10, n, n-1]==n-2, Print[n]], {n, 2, 10^8}]

Extensions

Corrected and extended by Max Alekseyev, Oct 12 2012