%I
%S 0,4,14,32,77,192,452,1024,2299,5120,11270,24576,53241,114688,245768,
%T 524288,1114103,2359296,4980746,10485760,22020085,46137344,96469004,
%U 201326592,419430387,872415232,1811939342,3758096384,7784628209
%N 2^(n1) times coefficient of x in (1+x)^n mod U(n,x), U the Chebyshev polynomials.
%F Apparently, a(n+1) = (n+1)2^n  (n+2)/4 * (I^n + (I)^n).
%F Empirical g.f.: x^2*(x+2)*(x^22*x+2) / ((2*x1)^2*(x^2+1)^2).  _Colin Barker_, Jul 16 2013
%Y Cf. A099586.
%K nonn
%O 1,2
%A _Ralf Stephan_, Oct 24 2004
