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 A139801 #2 Mar 30 2012 18:51:58 %S A139801 1,2,2,2,3,3,3,6,9,9,3,6,10,14,14,4,10,20,34,48,48,4,10,20,35,55,75, %T A139801 75,5,15,35,70,125,200,275,275,5,15,35,70,126,209,319,429,429,6,21,56, %U A139801 126,252,461,780,1209,1638,1638 %N A139801 A139687(n) (1, 1, 1, 2, 2, 1) differences by rows, 0's deleted (*).Triangle on line. %C A139801 (*) Full Triangle: %C A139801 0; %C A139801 1, 0; %C A139801 2, 2, 0; %C A139801 2, 3, 3, 0; %C A139801 3, 6, 9, 9, 0; %C A139801 3, 6, 10, 14, 14, 0; %F A139801 Even rows (with a leading 1) are in A139687.Must be separated from odd rows. %K A139801 nonn,tabl,uned %O A139801 0,2 %A A139801 _Paul Curtz_, Jun 14 2008