2^(n-1) times coefficient of x in (1+x)^n mod U(n,x), U the Chebyshev polynomials.

Terms

a(0) =0a(1) =4a(2) =14a(3) =32a(4) =77a(5) =192a(6) =452a(7) =1024a(8) =2299a(9) =5120a(10) =11270a(11) =24576a(12) =53241a(13) =114688a(14) =245768a(15) =524288a(16) =1114103a(17) =2359296a(18) =4980746a(19) =10485760a(20) =22020085a(21) =46137344a(22) =96469004a(23) =201326592a(24) =419430387a(25) =872415232a(26) =1811939342a(27) =3758096384a(28) =7784628209