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

Terms

a(0) =1a(1) =-1a(2) =1a(3) =1a(4) =-5a(5) =1a(6) =-1a(7) =12a(8) =-9a(9) =1a(10) =1a(11) =-22a(12) =39a(13) =-13a(14) =1a(15) =-1a(16) =35a(17) =-115a(18) =82a(19) =-17a(20) =1a(21) =1a(22) =-51a(23) =270a(24) =-344a(25) =141a(26) =-21a(27) =1a(28) =-1a(29) =70