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 A193418 #31 Nov 02 2013 21:14:12 %S A193418 1,3,8,23,69,206,616,1846,5537,16609,49824,149469,448405,1345212, %T A193418 4035632,12106892,36320673,108962015,326886040,980658115,2941974341, %U A193418 8825923018,26477769048,79433307138,238299921409,714899764221,2144699292656 %N A193418 Expansion of x*(x^2+x-1)/(3*x^6-4*x^5+x^4-3*x^2+4*x-1). %C A193418 Conjecture: log(A005960-a(n)) ~ (log(2)*(2*n-11)). %F A193418 a(n) = b(n+1,3)-b(n+1,4) with b(n,c) = sum(floor(3^m/2^c), m=1..n). %F A193418 G.f.: x*(x^2+x-1) / (3*x^6-4*x^5+x^4-3*x^2+4*x-1). %F A193418 a(n) = (9*3^n+4*n+1-(1+(-1)^n)*(1+4*i^n))/32, where i=sqrt(-1). - _Bruno Berselli_, Jul 30 2011 %Y A193418 Cf. A005960. %K A193418 nonn %O A193418 1,2 %A A193418 _Yalcin Aktar_, Jul 26 2011