A045596 Numbers k that divide 7^k + 5^k.

1, 2, 3, 9, 27, 39, 74, 81, 117, 243, 351, 507, 729, 1053, 1521, 2187, 2738, 3081, 3159, 4563, 6123, 6561, 6591, 9243, 9477, 12207, 13689, 18369, 19683, 19773, 27729, 28431, 36621, 40053, 41067, 43882, 55107, 59049, 59319, 79599, 83187, 85293

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..141 (All terms up to 10^7)

Crossrefs

Cf. A074616.

Programs

Mathematica

Select[Range[86000],Mod[PowerMod[7,#,#]+PowerMod[5,#,#],#]==0&] (* Harvey P. Dale, Aug 02 2023 *)