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 A175512 #10 Jul 16 2022 11:54:31
%S A175512 0,1,1,3,2,4,4,7,1,3,5,1,0,2,4,4,7,1,3,16,19,9,16,1,22,8,10,21,5,28,
%T A175512 22,7,28,6,17,28,4,16,19,22,25,10,40,43,28,3,34,40,31,34,13,40,8,1,49,
%U A175512 43,10,9,34,19,22,8,19,40,52,64,0,66,37,49,52,55,58,70,37,49,11,64,6,25,28,67,43,55,40,20,64,13,8,28,49,34,82,0,79,82,85,61,73,67
%N A175512 (Digit sum of 7^n) mod n.
%t A175512 Table[Mod[Plus@@IntegerDigits[7^n],n],{n,150}] (* _Harvey P. Dale_, Dec 16 2010 *)
%Y A175512 Cf. A000420, A066003, A067863; A000079, A001370, A175434, A175169.
%K A175512 base,nonn
%O A175512 1,4
%A A175512 _N. J. A. Sloane_, Dec 03 2010