Expansion of g.f. 1+x+(1+3*x+x^2)/(1+x)^3.

Terms

a(0) =2a(1) =1a(2) =-2a(3) =5a(4) =-9a(5) =14a(6) =-20a(7) =27a(8) =-35a(9) =44a(10) =-54a(11) =65a(12) =-77a(13) =90a(14) =-104a(15) =119a(16) =-135a(17) =152a(18) =-170a(19) =189a(20) =-209a(21) =230a(22) =-252a(23) =275a(24) =-299a(25) =324a(26) =-350a(27) =377a(28) =-405a(29) =434