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

Terms

a(0) =1a(1) =-2a(2) =1a(3) =4a(4) =-5a(5) =1a(6) =-8a(7) =18a(8) =-8a(9) =1a(10) =16a(11) =-56a(12) =41a(13) =-11a(14) =1a(15) =-32a(16) =160a(17) =-170a(18) =73a(19) =-14a(20) =1a(21) =64a(22) =-432a(23) =620a(24) =-377a(25) =114a(26) =-17a(27) =1a(28) =-128a(29) =1120