G.f.: Sum_{k>=0} (-1)^k * k! * x^(k*(k + 1)/2) / Product_{j=1..k} (1 - x^j).

Terms

a(0) =1a(1) =-1a(2) =-1a(3) =1a(4) =1a(5) =3a(6) =-3a(7) =-1a(8) =-7a(9) =-11a(10) =7a(11) =3a(12) =15a(13) =35a(14) =71a(15) =-35a(16) =25a(17) =-57a(18) =-99a(19) =-277a(20) =-415a(21) =25a(22) =-185a(23) =39a(24) =327a(25) =1079a(26) =1895a(27) =3745a(28) =-71a(29) =2907