Expansion of x^2*(1+x-x^2)/(1-2*x-4*x^2+x^3+x^4).

Terms

a(0) =0a(1) =1a(2) =3a(3) =9a(4) =29a(5) =90a(6) =284a(7) =890a(8) =2797a(9) =8780a(10) =27574a(11) =86581a(12) =271881a(13) =853732a(14) =2680833a(15) =8418132a(16) =26433983a(17) =83005929a(18) =260648825a(19) =818469251a(20) =2570093890a(21) =8070410030a(22) =25342077544a(23) =79577232067a(24) =249882270390a(25) =784660981474