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 A169890 #13 Mar 02 2017 23:07:56 %S A169890 0,1,3,6,0,5,1,8,6,5,15,26,38,41,55,60,76,83,91,0,20,41,63,86,0,25,41, %T A169890 68,86,5,35,66,98,21,55,80,16,43,71,0,40,81,23,66,0,45,81,28,66,5,55, %U A169890 6,58,1,55,0,56,3,51,0,60,21,83,46,0,65,21,88,46,5,75,46,18,81,55,20,96,63,31 %N A169890 Carryless sum 1+2+3+...+n. %C A169890 Carryless analog of triangular numbers. %H A169890 Rémy Sigrist, <a href="/A169890/b169890.txt">Table of n, a(n) for n = 0..9999</a> %H A169890 David Applegate, Marc LeBrun and N. J. A. Sloane, <a href="http://neilsloane.com/doc/carry1.pdf">Carryless Arithmetic (I): The Mod 10 Version</a>. %H A169890 <a href="/index/Ca#CARRYLESS">Index entries for sequences related to carryless arithmetic</a> %Y A169890 Cf. A004250, A059729. %K A169890 nonn,base,look %O A169890 0,3 %A A169890 _David Applegate_, _Marc LeBrun_ and _N. J. A. Sloane_, Jul 06 2010