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 A134429 #22 Nov 08 2022 13:59:30
%S A134429 3,-5,3,-5,11,-13,11,-13,19,-21,19,-21,27,-29,27,-29,35,-37,35,-37,43,
%T A134429 -45,43,-45,51,-53,51,-53,59,-61,59,-61,67,-69,67,-69,75,-77,75,-77,
%U A134429 83,-85,83,-85,91,-93,91,-93,99,-101,99,-101,107,-109,107,-109,115,-117,115,-117,123,-125,123,-125,131,-133,131
%N A134429 a(n) = (-1)^(1 + n) * 2 * ( -1/2 -n + (-1)^((1 + n)*(2 + n)/2)).
%C A134429 Previous name was: Array read by rows: row n lists 4 terms: k, m, k, m where k = 8n+3 and m = -8n -5.
%H A134429 B. D. Swan, <a href="/A134429/b134429.txt">Table of n, a(n) for n = 0..100000</a>
%F A134429 a(2*n) + a(2*n+1) = -2.
%F A134429 a(n) = (-1)^(1 + n) * 2 * ( -1/2 -n + (-1)^((1 + n)*(2 + n)/2)). - _Gerry Martens_, Nov 08 2022
%t A134429 Table[With[{k=8n+3,m=-8n-5},{k,m,k,m}],{n,0,30}]//Flatten (* _Harvey P. Dale_, Jul 18 2018 *)
%Y A134429 Cf. A134314 (first differences).
%K A134429 sign,easy,less
%O A134429 0,1
%A A134429 _Paul Curtz_, Jan 31 2008
%E A134429 Edited by _Omar E. Pol_, Mar 23 2008
%E A134429 Edited by B. D. Swan (bdswan(AT)gmail.com), Dec 20 2008
%E A134429 New name (using formula from _Gerry Martens_) from _Joerg Arndt_, Nov 08 2022