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 A318931 #8 Dec 24 2018 16:21:14 %S A318931 -1,-1,-2,1,0,2,7,-2,6,10,-4,5,4,6,10,0,-8,12,2,0,12,5,5,4,-3,3,-1,7, %T A318931 2,1,3,3 %N A318931 a(n) = A081287(n) - n. %C A318931 _Ed Pegg Jr_ remarks that the terms so far are remarkably small. %D A318931 Ed Pegg, Jr., Email to N. J. A. Sloane, Feb 14 2008 %Y A318931 Cf. A081287. %K A318931 sign,more %O A318931 1,3 %A A318931 _N. J. A. Sloane_, Sep 12 2018