This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A057263 #7 Nov 21 2013 12:47:25
%S A057263 1,3,7,9,21,27,49,63,81,93,99,147,189,243,343,387,441,539,567,729,777,
%T A057263 1029,1323,1701,1953,1971,2079,2183,2187,2401,3087,3969,5103,6561,
%U A057263 7077,7203,7533,8019,9261,9423,11277,11319,11907,15309,16807,17739,19683
%N A057263 Numbers n such that n | 12^n + 11^n + 10^n + 9^n + 8^n + 7^n + 6^n.
%t A057263 Select[ Range[ 10^5 ], Mod[ PowerMod[ 12, #, # ] + PowerMod[ 11, #, # ] + PowerMod[ 10, #, # ] + PowerMod[ 9, #, # ] + PowerMod[ 8, #, # ] + PowerMod[ 7, #, # ] + PowerMod[ 6, #, # ], # ] == 0 & ]
%t A057263 With[{c=Range[6,12]},Select[Range[20000],Divisible[Total[c^#],#]&]] (* _Harvey P. Dale_, Feb 29 2012 *)
%K A057263 nonn
%O A057263 1,2
%A A057263 _Robert G. Wilson v_, Sep 22 2000