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 A284722 #5 Apr 04 2017 06:59:18 %S A284722 -1,-1,1,2,2,4,5,4,7,8,8,10,11,11,13,14,14,16,17,17,19,20,19,22,23,23, %T A284722 25,26,26,28,29,29,31,32,32,34,35,34,37,38,38,40,41,41,43,44,44,46,47, %U A284722 47,49,50,47,52,53,53,55,56,56,58,59,59,61,62,62,64,65,64,67,68,68,70,71,71,73,74,74 %N A284722 (2n+1-A284721(n))/2. %Y A284722 Cf. A284721. %K A284722 sign %O A284722 0,4 %A A284722 _N. J. A. Sloane_, Apr 04 2017