Riordan array (1-x, x(1-x)/(1+x)).

Terms

a(0) =1a(1) =-1a(2) =1a(3) =0a(4) =-3a(5) =1a(6) =0a(7) =4a(8) =-5a(9) =1a(10) =0a(11) =-4a(12) =12a(13) =-7a(14) =1a(15) =0a(16) =4a(17) =-20a(18) =24a(19) =-9a(20) =1a(21) =0a(22) =-4a(23) =28a(24) =-56a(25) =40a(26) =-11a(27) =1a(28) =0a(29) =4