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

Terms

a(0) =1a(1) =0a(2) =12a(3) =8a(4) =108a(5) =160a(6) =960a(7) =2144a(8) =9040a(9) =24832a(10) =89664a(11) =270976a(12) =916416a(13) =2885120a(14) =9500160a(15) =30412288a(16) =99084544a(17) =319299584a(18) =1035979776a(19) =3347073024a(20) =10842246144a(21) =35064422400a(22) =113514577920a(23) =367253348352