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 A071958 #17 May 17 2024 04:21:20
%S A071958 67,99,115,147,163,187,267,275,283,307,315,355,379,403,427,475,507,
%T A071958 523,531,595,619,643,675,747,763,787,883,907,931,947,955,975,1003,
%U A071958 1027,1107,1123,1147,1179,1203,1267,1275,1347,1363,1387,1395,1435,1467,1475
%N A071958 Numbers k such that Sum_{i=0..k} K(k, i) < 0 where K(x, y) is the Kronecker symbol (x/y).
%H A071958 Robert G. Wilson v, <a href="/A071958/b071958.txt">Table of n, a(n) for n = 1..1000</a>
%t A071958 f[n_] := Sum[ KroneckerSymbol[n, k], {k, 0, n}]; Select[ Range@ 1500, f[#] < 0 &] (* _Robert G. Wilson v_, Mar 21 2015 *)
%o A071958 (PARI) for(n=1, 1800, if(sum(i=0, n, kronecker(n,i)) < 0, print1(n,",")))
%o A071958 (SageMath)
%o A071958 print([n for n in range(999) if sum(kronecker(n, k)
%o A071958 for k in range(n + 1)) < 0]) # _Peter Luschny_, May 16 2024
%Y A071958 Cf. A071961.
%K A071958 easy,nonn
%O A071958 1,1
%A A071958 _Benoit Cloitre_, Jun 16 2002
%E A071958 Summation range set to {i=0..k} by _Peter Luschny_, May 16 2024