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 A137766 #8 Jun 22 2013 16:06:10 %S A137766 1,2,1,3,7,12,1,4,9,20,1,5,49,60,11,30,1,6,71,105,13,42,1,7,351,280, %T A137766 97,168,15,56,1,8,545,504,127,252,17,72,1,9,2561,1260,799,840,161,360, %U A137766 19,90,1,10,4159,2310,1121,1320,199,495,21,110,1,11 %N A137766 Elements to the right of the central element in writing first the numerator and then the denominator (left to right) of Leibniz's harmonic-like triangle. %e A137766 1/1; --> %e A137766 1/2, 1/2; --> 1 2 %e A137766 1/3, 5/6, 1/3; --> 1 3 %e A137766 1/4, 7/12, 7/12, 1/4; --> ... %e A137766 1/5, 9/20, 31/30, 9/20, 1/5; %Y A137766 Cf. A137752. %Y A137766 Cf. A046201, A046204, A046205, A046206, A046208, A046212, A137752, A137753, A137754, A137755, A137756, A137757, A137758, A137759, A137760, A137761, A137762, A137763, A137764, A137765. %K A137766 nonn,tabf,frac,less %O A137766 1,2 %A A137766 _Mohammad K. Azarian_, Feb 13 2008