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 A175434 #14 Aug 12 2014 13:07:39
%S A175434 0,0,2,3,0,4,4,5,8,7,3,7,7,8,11,9,14,1,10,11,5,3,18,13,4,14,8,15,12,7,
%T A175434 16,26,29,27,24,28,19,29,32,21,9,4,13,14,17,24,21,25,16,26,29,27,24,
%U A175434 28,37,29,23,12,18,22,13,23,26,24,21,43,43,35,20,0,15,37,37,56,50,30,27,22,31,32,26,42,39,34,43,26,20,27,24,28,55,47,32,57,45,31,40,14,8,15
%N A175434 (Digit sum of 2^n) mod n.
%e A175434 For n = 1,2,3,4,5,6, the digit-sum of 2^n is 2,4,8,7,5,10, so
%e A175434 a(1) through a(6) are 0,0,2,3,0,4. - _N. J. A. Sloane_, Aug 12 2014
%t A175434 Table[Mod[Total[IntegerDigits[2^n]],n],{n,100}] (* _Harvey P. Dale_, Aug 12 2014 *)
%Y A175434 Sum of digits of k^n mod n: (k=2) A000079, A001370, A175434, A175169; (k=3) A000244, A004166, A175435, A067862; (k=5) A000351, A066001, A175456; (k=6) A000400, A066002, A175457, A067864; (k=7) A000420, A066003, A175512, A067863; (k=8) A062933; (k=13) A001022, A175527, A175528, A175525; (k=21) A175589; (k=167) A175558, A175559, A175560, A175552.
%K A175434 nonn,base
%O A175434 1,3
%A A175434 _N. J. A. Sloane_, Dec 03 2010
%E A175434 Offset changed to 1 at the suggestion of _Harvey P. Dale_, Aug 12 2014