Expansion of (1-2*x)/(1-4*x).

Terms

a(0) =1a(1) =2a(2) =8a(3) =32a(4) =128a(5) =512a(6) =2048a(7) =8192a(8) =32768a(9) =131072a(10) =524288a(11) =2097152a(12) =8388608a(13) =33554432a(14) =134217728a(15) =536870912a(16) =2147483648a(17) =8589934592a(18) =34359738368a(19) =137438953472a(20) =549755813888