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 A233131 #5 Oct 01 2018 16:52:36
%S A233131 0,0,0,0,0,1,2,4,2,5,9,14,9,15,21,28,24,33,27,37,33,44,56,69,52,66,81,
%T A233131 88,87,105,92,111,102,122,143,165,139,163,187,212,196,223,209,237,239,
%U A233131 244,274,305,266,298,296,330,335,371,347,384,368,407,447,488,432,474,516,529,513,558,543,590,599,647,637,687,620
%N A233131 Sum of remainders of n modulo all smaller composite numbers.
%F A233131 a(n) = A004125(n) - A024934(n).
%t A233131 Table[Total[Mod[n,Select[Range[n-1],CompositeQ]]],{n,0,80}] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Oct 01 2018 *)
%Y A233131 Cf. A143853, A233344
%K A233131 nonn
%O A233131 0,7
%A A233131 _Max Alekseyev_, Dec 07 2013