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

Terms

a(0) =0a(1) =1a(2) =4a(3) =14a(4) =52a(5) =195a(6) =728a(7) =2716a(8) =10136a(9) =37829a(10) =141180a(11) =526890a(12) =1966380a(13) =7338631a(14) =27388144a(15) =102213944a(16) =381467632a(17) =1423656585a(18) =5313158708a(19) =19828978246a(20) =74002754276a(21) =276182038859