Expansion of c(x*y*(1-x)), c(x) the g.f. of A000108.

Terms

a(0) =1a(1) =0a(2) =1a(3) =0a(4) =-1a(5) =2a(6) =0a(7) =0a(8) =-4a(9) =5a(10) =0a(11) =0a(12) =2a(13) =-15a(14) =14a(15) =0a(16) =0a(17) =0a(18) =15a(19) =-56a(20) =42a(21) =0a(22) =0a(23) =0a(24) =-5a(25) =84a(26) =-210a(27) =132a(28) =0a(29) =0