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 A117004 #20 Jan 01 2020 13:35:54
%S A117004 1,2,2,4,2,6,2,6,5,6,2,12,2,6,8,10,2,12,2,14,8,6,2,20,7,6,8,14,2,22,2,
%T A117004 14,8,6,12,26,2,6,8,24,2,24,2,14,18,6,2,32,9,16,8,14,2,24,12,28,8,6,2,
%U A117004 42,2,6,22,22,12,24,2,14,8,30,2,48,2,6,18,14,16,24,2,40,17,6,2,46,12,6,8,30
%N A117004 a(n) = sigma(n) - A079667(n).
%D A117004 H. J. S. Smith, Report on the Theory of Numbers, reprinted in Vol. 1 of his Collected Math. Papers, Chelsea, NY, 1979, see p. 322.
%H A117004 Seiichi Manyama, <a href="/A117004/b117004.txt">Table of n, a(n) for n = 1..10000</a>
%F A117004 G.f.: sum(n>=1, n*x^(n^2)*(1+x^n)/(1-x^n) ). [_Joerg Arndt_, Jan 30 2011]
%F A117004 a(n) = Sum_{d|n} min(d, n/d). - _Seiichi Manyama_, Dec 27 2017
%t A117004 Table[Total[Min[#,n/#]&/@Divisors[n]],{n,90}] (* _Harvey P. Dale_, Jan 01 2020 *)
%o A117004 (PARI) {a(n) = sumdiv(n, d, min(d, n/d))} \\ _Seiichi Manyama_, Dec 27 2017
%Y A117004 Cf. A000203, A079667.
%K A117004 nonn
%O A117004 1,2
%A A117004 _N. J. A. Sloane_, Apr 15 2006