Riordan array ((1-x^2)/(1+3x+x^2),x/(1+3x+x^2)).

Terms

a(0) =1a(1) =-3a(2) =1a(3) =7a(4) =-6a(5) =1a(6) =-18a(7) =24a(8) =-9a(9) =1a(10) =47a(11) =-84a(12) =50a(13) =-12a(14) =1a(15) =-123a(16) =275a(17) =-225a(18) =85a(19) =-15a(20) =1a(21) =322a(22) =-864a(23) =900a(24) =-468a(25) =129a(26) =-18a(27) =1a(28) =-843a(29) =2639