A045592 Numbers k that divide 7^k + 4^k.

1, 11, 121, 253, 737, 1331, 2783, 5819, 8107, 14641, 16951, 30613, 49379, 64009, 89177, 116897, 133837, 161051, 186461, 336743, 389873, 543169, 640343, 704099, 980947, 1135717, 1285867, 1292071, 1472207, 1771561, 2051071, 2688631

Offset: 1

Author

David W. Wilson

Keywords

• nonn

Crossrefs

Cf. A074613.

Programs

Mathematica

Select[Range[269*10^4],Mod[PowerMod[7,#,#]+PowerMod[4,#,#],#]==0&] (* Harvey P. Dale, Jun 25 2021 *)