Expansion of g.f. (1+x)/(1+2*x+4*x^2).

Terms

a(0) =1a(1) =-1a(2) =-2a(3) =8a(4) =-8a(5) =-16a(6) =64a(7) =-64a(8) =-128a(9) =512a(10) =-512a(11) =-1024a(12) =4096a(13) =-4096a(14) =-8192a(15) =32768a(16) =-32768a(17) =-65536a(18) =262144a(19) =-262144a(20) =-524288a(21) =2097152a(22) =-2097152a(23) =-4194304a(24) =16777216a(25) =-16777216a(26) =-33554432a(27) =134217728a(28) =-134217728a(29) =-268435456