Riordan array ((1-x+sqrt(1-6x+x^2))/2, (1+x-sqrt(1-6x+x^2))/4).

Terms

a(0) =1a(1) =-2a(2) =1a(3) =-2a(4) =-1a(5) =1a(6) =-6a(7) =-1a(8) =0a(9) =1a(10) =-22a(11) =-3a(12) =1a(13) =1a(14) =1a(15) =-90a(16) =-11a(17) =4a(18) =4a(19) =2a(20) =1a(21) =-394a(22) =-45a(23) =17a(24) =16a(25) =8a(26) =3a(27) =1a(28) =-1806a(29) =-197