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 A330386 #10 Dec 12 2019 14:59:29
%S A330386 1,4,0,9,16,4,9,1,16,0,25,36,49,25,64,81,100,121,144,100,64,36,16,49,
%T A330386 9,36,4,49,1,36,121,49,100,36,169,256,196,225,256,361,484,400,441,484,
%U A330386 625,529,576,625,784,841,900,961,1024,1089,1156,1225,1296,1369
%N A330386 Running totals in A330385.
%C A330386 All terms are nonnegative squares.
%H A330386 Rémy Sigrist, <a href="/A330386/b330386.txt">Table of n, a(n) for n = 1..10000</a>
%H A330386 Rémy Sigrist, <a href="/A330386/a330386.png">Scatterplot of the first 5000000 terms</a>
%F A330386 a(n) = - Sum_{k = 1..n } A330385(k) * (-1)^A330385(k).
%o A330386 (PARI) s=t=0; for (n=1, 58, for (v=1, oo, if (!bittest(s,v) && issquare(u=t-v*(-1)^v), print1 (t=u ", "); s+=2^v; break)))
%Y A330386 Cf. A000290, A330385.
%K A330386 nonn,look
%O A330386 1,2
%A A330386 _Rémy Sigrist_, Dec 12 2019