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 A141245 #2 Mar 30 2012 18:59:21 %S A141245 1,3,3,13,13,27,27,221,221,449,449,1817,1817,3667,3667,59101,59101, %T A141245 118917,118917,478099,478099,960397,960397,7712569,7712569,15477141, %U A141245 15477141,62094289,62094289,124522883,124522883,3994427101 %N A141245 Numerators in expansion of (1+x-sqrt(1-x^2))/(x(1-x)). %C A141245 The denominators in the expansion of (1+x-sqrt(1-x^2))/(x(1-x)) are 1,2,2,8,8,16,16,.... %C A141245 The sequence 1,3/2,3/2,13/8,13/8,... is the image of 2n+1 under the %C A141245 Chebyshev related (rational) Riordan array c((x/2)^2),(x/2)c((x/2)^2)) with c(x) the g.f. of A000108. %C A141245 The Hankel transform of fraction sequence is (-1)^n*(2n+1)/4^comb(n+1,2). %Y A141245 Cf. A141244. %K A141245 easy,frac,nonn %O A141245 0,2 %A A141245 _Paul Barry_, Jun 17 2008