Expansion of Sum_{k>=0} x^(k*(k+1)) / Product_{j=1..k} (1 - j*x^j).

Terms

a(0) =1a(1) =0a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =2a(8) =4a(9) =4a(10) =8a(11) =8a(12) =17a(13) =17a(14) =35a(15) =38a(16) =74a(17) =80a(18) =161a(19) =173a(20) =336a(21) =387a(22) =713a(23) =818a(24) =1555a(25) =1765a(26) =3248a(27) =3923a(28) =6905a(29) =8282