Triangle, read by rows, where the n-th row lists the (2n+1) coefficients of (1 + x - 2*x^2)^n.

Terms

a(0) =1a(1) =1a(2) =1a(3) =-2a(4) =1a(5) =2a(6) =-3a(7) =-4a(8) =4a(9) =1a(10) =3a(11) =-3a(12) =-11a(13) =6a(14) =12a(15) =-8a(16) =1a(17) =4a(18) =-2a(19) =-20a(20) =1a(21) =40a(22) =-8a(23) =-32a(24) =16a(25) =1a(26) =5a(27) =0a(28) =-30a(29) =-15