G.f.: Product_{k>=1} 1/(1+x^k)^k.

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =-2a(4) =1a(5) =0a(6) =4a(7) =2a(8) =8a(9) =-2a(10) =4a(11) =-11a(12) =-1a(13) =-25a(14) =-5a(15) =-35a(16) =13a(17) =-26a(18) =49a(19) =-6a(20) =110a(21) =6a(22) =159a(23) =-23a(24) =182a(25) =-141a(26) =129a(27) =-358a(28) =62a(29) =-640