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 A171958 #6 Dec 24 2021 08:12:40 %S A171958 0,1,-1,2,-2,2,0,-1,5,-6,5,-5,2,4,-1,-1,-4,5,-2,-3,3,-1,7,-9,4,5,-6,3, %T A171958 8,-14,6,-3,2,10,-15,5,-2,2,-3,15,-17,6,5,-11,3,5,-8,3,0,-2,41,-42,5, %U A171958 10,5,-20,4,28,-32,3,8,7,-18,4,3,-7,3,4,-4,-1,29,-31,6,25,-28,3,-3,-1,6,25,-33,9,47,-56,3,5,-1,12,-19,5,32,-37,3 %N A171958 First differences of A181391. %H A171958 Rémy Sigrist, <a href="/A171958/b171958.txt">Table of n, a(n) for n = 1..10000</a> %H A171958 Rémy Sigrist, <a href="/A171958/a171958.txt">C++ program for A171958</a> %o A171958 (C++) See Links section. %Y A171958 Cf. A181391. %K A171958 sign %O A171958 1,4 %A A171958 _N. J. A. Sloane_, Nov 02 2010