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 A137718 #5 Jun 27 2013 13:36:02 %S A137718 1,-4,2,4,-8,8,8,-32,16,32,-64,64,64,-256,128,256,-512,512,512,-2048, %T A137718 1024,2048,-4096,4096,4096,-16384,8192,16384,-32768,32768,32768, %U A137718 -131072,65536,131072,-262144,262144,262144 %N A137718 A scaled Hankel transform. %C A137718 A137717=2^floor(n/2)*a(n) is the Hankel transform of A106191. %F A137718 a(n)=A137717(n)/2^floor(n/2). %F A137718 Empirical g.f.: -(4*x^3-4*x^2+4*x-1) / (4*x^4+2*x^2+1). - _Colin Barker_, Jun 27 2013 %Y A137718 Cf. A137719. %K A137718 easy,sign %O A137718 0,2 %A A137718 _Paul Barry_, Feb 08 2008