Expansion of Product_{k>=1} (1-x^k)^40.

Terms

a(0) =1a(1) =-40a(2) =740a(3) =-8320a(4) =62530a(5) =-322048a(6) =1085240a(7) =-1799680a(8) =-2821065a(9) =26012480a(10) =-66837420a(11) =35093760a(12) =268749870a(13) =-783902720a(14) =526221400a(15) =1691816960a(16) =-3960854625a(17) =1042577120a(18) =5103133240a(19) =-380798080a(20) =-10159511430