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 A137757 #7 Jun 22 2013 16:06:10 %S A137757 2,2,3,6,5,3,4,12,7,12,7,4,5,20,9,30,31,20,9,5,6,30,11,60,49,60,49,30, %T A137757 11,6,7,42,13,105,71,140,209,105,71,42,13,7,8,56,15,168,97,280,351, %U A137757 280,351,168,97,56,15,8,9,72,17,252,127,504,545,630,1471 %N A137757 Nontrivial elements in writing the denominator of an element first and then the numerator of that element (left to right) of Leibniz's harmonic-like triangle. That is, the nontrivial elements of A137753. %e A137757 1/1; --> %e A137757 1/2, 1/2; --> 2 2 %e A137757 1/3, 5/6, 1/3; --> 3 6 5 3 %e A137757 1/4, 7/12, 7/12, 1/4; --> ... %e A137757 1/5, 9/20, 31/30, 9/20, 1/5; %Y A137757 Cf. A003506; A007622; A046201; A046204; A046205; A046206; A046208; A046212; A137752; A137753; A137754; A137755; A137756. %K A137757 frac,nonn,tabf,less %O A137757 1,1 %A A137757 _Mohammad K. Azarian_, Feb 10 2008