Expansion of g.f.: 2*x*(1-x)/((1-2*x)*(1-2*x^2)).

Terms

a(0) =0a(1) =2a(2) =2a(3) =8a(4) =12a(5) =32a(6) =56a(7) =128a(8) =240a(9) =512a(10) =992a(11) =2048a(12) =4032a(13) =8192a(14) =16256a(15) =32768a(16) =65280a(17) =131072a(18) =261632a(19) =524288a(20) =1047552a(21) =2097152a(22) =4192256a(23) =8388608a(24) =16773120a(25) =33554432a(26) =67100672a(27) =134217728a(28) =268419072a(29) =536870912