Expansion of Product_{k>=1} (1 - x^k)^20.

Terms

a(0) =1a(1) =-20a(2) =170a(3) =-760a(4) =1615a(5) =476a(6) =-11210a(7) =22440a(8) =1615a(9) =-64600a(10) =60002a(11) =51680a(12) =-9520a(13) =-213180a(14) =-83980a(15) =803528a(16) =-379525a(17) =-692360a(18) =119700a(19) =80920a(20) =1899830a(21) =-1235360a(22) =-755990a(23) =-1200040a(24) =-1981435a(25) =8388956a(26) =-361760a(27) =-5068440