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

Terms

a(0) =0a(1) =1a(2) =4a(3) =16a(4) =65a(5) =263a(6) =1065a(7) =4312a(8) =17459a(9) =70690a(10) =286218a(11) =1158873a(12) =4692181a(13) =18998253a(14) =76922356a(15) =311452261a(16) =1261044460a(17) =5105864780a(18) =20673224441a(19) =83704176903a(20) =338911293253