Triangle Id-(xc(x),xc(x)), c(x) the g.f. of the Catalan numbers A000108.

Terms

a(0) =1a(1) =-1a(2) =1a(3) =-1a(4) =-1a(5) =1a(6) =-2a(7) =-2a(8) =-1a(9) =1a(10) =-5a(11) =-5a(12) =-3a(13) =-1a(14) =1a(15) =-14a(16) =-14a(17) =-9a(18) =-4a(19) =-1a(20) =1a(21) =-42a(22) =-42a(23) =-28a(24) =-14a(25) =-5a(26) =-1a(27) =1a(28) =-132a(29) =-132