Expansion of (1/x) * Series_Reversion( x*(1+x+x^3)/(1+x)^3 ).

Terms

a(0) =1a(1) =2a(2) =5a(3) =13a(4) =33a(5) =77a(6) =147a(7) =128a(8) =-726a(9) =-5870a(10) =-28918a(11) =-117501a(12) =-419748a(13) =-1330265a(14) =-3631065a(15) =-7585458a(16) =-5021553a(17) =62555365a(18) =485450778a(19) =2473377984a(20) =10459876208a(21) =38765746168a(22) =126610935508a(23) =352046019398a(24) =725506704096a(25) =264040020875