Expansion of Product_{k>0} (1+sqrt(1-4*x^k))/2.

Terms

a(0) =1a(1) =-1a(2) =-2a(3) =-2a(4) =-5a(5) =-9a(6) =-36a(7) =-104a(8) =-365a(9) =-1219a(10) =-4213a(11) =-14617a(12) =-51570a(13) =-183084a(14) =-656536a(15) =-2370066a(16) =-8613590a(17) =-31478538a(18) =-115632718a(19) =-426676244a(20) =-1580878746a(21) =-5878933054a(22) =-21936060630a(23) =-82100980070a(24) =-308146839623