%I #7 May 25 2024 23:35:32
%S 1,3,7,9,21,27,49,63,77,81,147,189,243,297,343,369,441,567,729,903,
%T 1029,1323,1617,1631,1701,2009,2037,2043,2187,2401,2597,2709,3087,
%U 3969,5103,6237,6321,6561,7203,8001,8127,9261,10209,11907,13203,15309,15477
%N Numbers k such that k | 6^k + 5^k + 4^k + 3^k + 2^k + 1^k.
%t Do[ If[ Mod[ PowerMod[ 6, n, n ] + PowerMod[ 5, n, n ] + PowerMod[ 4, n, n ] + PowerMod[ 3, n, n ] + PowerMod[ 2, n, n ] + 1, n ] == 0, Print[ n ] ], {n, 1, 10^6} ]
%t Select[Range[16000],Divisible[Total[Range[6]^#],#]&] (* _Harvey P. Dale_, Jun 06 2013 *)
%Y Cf. A001553.
%K nonn
%O 1,2
%A _Robert G. Wilson v_, Aug 25 2000