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Numbers n such that n | 7^n + 6^n + 5^n + 4^n.
0

%I #4 Mar 30 2012 17:30:26

%S 1,2,6,11,14,98,121,253,686,1331,1969,2783,4802,5819,13211,14641,

%T 22627,30613,33614,39634,45991,60643,64009,65198,87967,133837,159643,

%U 161051,172186,184026,192533,235298,278179,336743,667073,704099,967637

%N Numbers n such that n | 7^n + 6^n + 5^n + 4^n.

%t Select[ Range[ 1, 10^6 ], Mod[ PowerMod[ 7, #, # ] + PowerMod[ 6, #, # ] + PowerMod[ 5, #, # ] + PowerMod[ 4, #, # ], # ] == 0 & ]

%K nonn

%O 1,2

%A _Robert G. Wilson v_, Sep 20 2000