A056643 Numbers n such that n | 4^n + 3^n + 2^n + 1^n.

1, 2, 5, 6, 10, 25, 30, 50, 65, 125, 150, 190, 250, 625, 750, 978, 1250, 1558, 1625, 2405, 2425, 2575, 3125, 3750, 3890, 5050, 6250, 13250, 15150, 15625, 18750, 25250, 31250, 40625, 71669, 72010, 75750, 78125, 93750, 95950, 96217, 99250, 115625

Offset: 1

Author

Robert G. Wilson v, Aug 25 2000

Keywords

• nonn

Crossrefs

Cf. A001551.

Programs

Mathematica

Do[ If[ Mod[ PowerMod[ 4, n, n ] + PowerMod[ 3, n, n ] + PowerMod[ 2, n, n ] + 1, n ] == 0, Print[ n ] ], {n, 1, 10^6} ]

Formula

All numbers of the forms 5^k, 2*5^k & 6*5^k are in the sequence. - Farideh Firoozbakht, Nov 21 2006