A177906 Numbers k such that k^3 divides 6^(k^2) - 1.

1, 5, 1555, 9673655, 24181805, 90993505, 200928005, 28298980055, 36850702555, 62488609555, 141377087255, 150435008905, 367279622065, 2256331679135, 7521049172905, 18802586659555, 24599612913355, 54706615318945

Offset: 1

Author

Alexander Adamchuk, May 16 2010

Keywords

• nonn

Comments

5 divides a(n) for n > 1.

Prime divisors of a(n) in order of their appearance are {5, 311, 6221, 15551, 18198701, 40185601, ...}.

From there on, the list is no longer increasing; it continues with 23698201, 90917741, 236192683, 93307, 311021, ... - M. F. Hasler, Oct 21 2012

Crossrefs

Cf. A014946 (k divides 6^k-1), A127106 (k^2 divides 6^k-1).

Cf. A129211, A129212, A177905, A177907, A127102, A177909, A177243.

Cf. A177911, A177912, A177913, A177914, A177915, A177916, A177917, A177918, A177919, A177920.

Programs

PARI

is_A177906(n)=Mod(6,n^3)^(n^2)==1  \\ M. F. Hasler, Oct 21 2012

Extensions

More terms from Max Alekseyev, Oct 02 2010