%I #3 Mar 30 2012 17:30:27
%S 1,7,49,343,2359,2401,16513,16807,115591,117649,794983,809137,823543
%N Numbers n such that n | 4^n + 2^n + 1.
%t Select[ Range[ 10^6 ], Mod[ PowerMod[ 4, #, # ] + PowerMod[ 2, #, # ] + 1, # ] == 0 & ]
%K nonn
%O 1,2
%A _Robert G. Wilson v_, Nov 09 2000
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