a(n) = [(x*y)^n] Product_{k>=1} (1 - x^k - y^k)^n.

Terms

a(0) =1a(1) =0a(2) =-2a(3) =-6a(4) =-82a(5) =530a(6) =-2420a(7) =11718a(8) =-77458a(9) =492834a(10) =-1022532a(11) =3574714a(12) =-39670180a(13) =-172880396a(14) =3186538080a(15) =-18558899356a(16) =150869023214