The unique sequence such that Sum_{d|n} d*a(d)^(n/d) = sigma(n)^2 for every n.

Terms

a(0) =1a(1) =4a(2) =5a(3) =4a(4) =7a(5) =-10a(6) =9a(7) =-44a(8) =-23a(9) =-197a(10) =13a(11) =-845a(12) =15a(13) =-2340a(14) =-701a(15) =-9164a(16) =19a(17) =-31578a(18) =21a(19) =-124979a(20) =-11355a(21) =-381326a(22) =25a(23) =-1778580a(24) =-3323a(25) =-5162265a(26) =-212899a(27) =-21915630a(28) =31a(29) =-70256029