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 A099590 #5 Apr 30 2014 01:27:40 %S A099590 0,4,14,32,77,192,452,1024,2299,5120,11270,24576,53241,114688,245768, %T A099590 524288,1114103,2359296,4980746,10485760,22020085,46137344,96469004, %U A099590 201326592,419430387,872415232,1811939342,3758096384,7784628209 %N A099590 2^(n-1) times coefficient of x in (1+x)^n mod U(n,x), U the Chebyshev polynomials. %F A099590 Apparently, a(n+1) = (n+1)2^n - (n+2)/4 * (I^n + (-I)^n). %F A099590 Empirical g.f.: x^2*(x+2)*(x^2-2*x+2) / ((2*x-1)^2*(x^2+1)^2). - _Colin Barker_, Jul 16 2013 %Y A099590 Cf. A099586. %K A099590 nonn %O A099590 1,2 %A A099590 _Ralf Stephan_, Oct 24 2004