G.f.: q^(2*n)* Product_{m=0..n-1} (1-q^(2*m+1))^2.

Terms

a(0) =1a(1) =0a(2) =1a(3) =-2a(4) =2a(5) =-2a(6) =2a(7) =-4a(8) =6a(9) =-6a(10) =7a(11) =-10a(12) =12a(13) =-12a(14) =16a(15) =-22a(16) =25a(17) =-28a(18) =34a(19) =-42a(20) =50a(21) =-56a(22) =64a(23) =-80a(24) =94a(25) =-104a(26) =122a(27) =-146a(28) =168a(29) =-190