G.f.: x / (Sum_{k>=1} x^k / (1 + x^k)^2).

Terms

a(0) =1a(1) =1a(2) =-3a(3) =-2a(4) =9a(5) =0a(6) =-32a(7) =18a(8) =108a(9) =-118a(10) =-333a(11) =576a(12) =911a(13) =-2466a(14) =-2040a(15) =9702a(16) =2529a(17) =-35622a(18) =8254a(19) =122436a(20) =-88275a(21) =-391882a(22) =501660a(23) =1148334a(24) =-2331810a(25) =-2949282a(26) =9689949a(27) =5791930a(28) =-37155906a(29) =-2645148