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 A137763 #14 Jun 22 2013 16:06:10 %S A137763 1,1,6,5,30,31,140,209,630,1471,2772,10625 %N A137763 Central elements in writing first the denominator and then the numerator(left to right) of Leibniz's harmonic-like triangle. %F A137763 a(2n) = A137762(2n-1); a(2n-1) = A137762(2n) = A046212(2n-1) = A056040(2n-1) = A100071(2n-1). - _M. F. Hasler_, Jan 25 2012 %e A137763 1/1; --> 1 1 %e A137763 1/2, 1/2; --> %e A137763 1/3, 5/6, 1/3; --> 6 5 %e A137763 1/4, 7/12, 7/12, 1/4; --> ... %e A137763 1/5, 9/20, 31/30, 9/20, 1/5; %Y A137763 Cf. A046201, A046204, A046205, A046206, A046208, A046212, A137752, A137753, A137754, A137755, A137756, A137757, A137758, A137759, A137760, A137761, A137762. %K A137763 nonn,tabf,frac,less %O A137763 1,3 %A A137763 _Mohammad K. Azarian_, Feb 13 2008