G.f.: A(x) = exp( Sum_{n>=1} sigma(n)*x^n/(1+x^n) /n ).

Terms

a(0) =1a(1) =1a(2) =1a(3) =3a(4) =2a(5) =4a(6) =7a(7) =7a(8) =9a(9) =14a(10) =18a(11) =20a(12) =31a(13) =34a(14) =42a(15) =61a(16) =69a(17) =83a(18) =109a(19) =127a(20) =156a(21) =203a(22) =228a(23) =276a(24) =347a(25) =404a(26) =477a(27) =591a(28) =683a(29) =801