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 A318737 #8 Sep 13 2018 18:15:22
%S A318737 1,9,25,49,85,133,169,225,445,845,973,1125,2205,2209,2469,2829,7929,
%T A318737 9429,9945,23569,24073,24645,26145,40425,68153,71289,72413,89517,
%U A318737 112233,112245,128973,162405,162409,162429,297073,477489,477493,502713,561253
%N A318737 Numbers n=2*k-1 where Sum_{j=1..k} (-1)^(j+1) * d(2*j-1) achieves a new record, with d(n) = number of divisors of n (A000005).
%H A318737 Hugo Pfoertner, <a href="/A318737/b318737.txt">Table of n, a(n) for n = 1..268</a>
%e A318737 a(2) = 9, because s = d(1)-d(3)+d(5)-d(7)+d(9) = 1-2+2-2+3 = 2 exceeds d(1)=1, d(1)-d(3)=-1, d(1)-d(3)+d(5)=1, d(1)-d(3)+d(5)-d(7)=-1.
%o A318737 (PARI) s=0;smax=0;j=-1;forstep(k=1,600000,2,j=-j;s=s+j*numdiv(k);if(s>smax,smax=s;print1(k,", ")))
%Y A318737 Cf. A000005, A099774, A318734, A318735, A318736, A318738.
%K A318737 nonn
%O A318737 1,2
%A A318737 _Hugo Pfoertner_, Sep 05 2018