Triangle inverse to that in A046899.

Terms

a(0) =1a(1) =-1a(2) =1a(3) =1a(4) =-3a(5) =2a(6) =1a(7) =3a(8) =-10a(9) =6a(10) =-1a(11) =9a(12) =10a(13) =-42a(14) =24a(15) =-17a(16) =21a(17) =50a(18) =42a(19) =-216a(20) =120a(21) =-107a(22) =-33a(23) =230a(24) =294a(25) =216a(26) =-1320a(27) =720a(28) =-415a(29) =-1173