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 A154589 #7 Dec 27 2013 19:13:29 %S A154589 4,-1,-2,-4,-8,-16,-32,-64,-128,-256,-512,-1024,-2048,-4096,-8192, %T A154589 -16384,-32768,-65536 %N A154589 a(n)=A154570(n)+A154570(n+1). %F A154589 G.f.: (4-9x)/(1-2x). a(n+1)= -A000079(n). _R. J. Mathar_, Feb 25 2009 %F A154589 E.g.f.: 5 + x/(G(0)+1), where G(k) = 2*k - 1 - x/(1 + x/G(k+1) ); (continued fraction ). - _Sergei N. Gladkovskii_, Dec 27 2013 %K A154589 sign,easy %O A154589 0,1 %A A154589 _Paul Curtz_, Jan 12 2009 %E A154589 Edited by _N. J. A. Sloane_, Jan 14 2009