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 A137760 #7 Jun 22 2013 16:06:10 %S A137760 1,2,3,5,6,4,7,12,9,20,31,30,11,49,60,13,42,71,105,209,140,8,15,56,97, %T A137760 168,351,280,17,72,127,252,545,504,1471,630,10,19,90,161,360,799,840, %U A137760 2561,1260,21,110,199,495,1121,1320,4159,2310,10625,2772 %N A137760 Distinct numbers in writing first numerator and then denominator (left to right) of Leibniz's harmonic-like triangle. %e A137760 1/1; --> 1 %e A137760 1/2, 1/2; --> 2 %e A137760 1/3, 5/6, 1/3; --> 3 5 6 %e A137760 1/4, 7/12, 7/12, 1/4; --> ... %e A137760 1/5, 9/20, 31/30, 9/20, 1/5; %Y A137760 Cf. A046201; A046204; A046205; A046206; A046208; A046212; A137752; A137753; A137754; A137755; A137756; A137757; A137758; A137759. %K A137760 frac,nonn,tabf,less %O A137760 1,2 %A A137760 _Mohammad K. Azarian_, Feb 11 2008