a(n) = Sum_{d|n} (-1)^(d-1) * binomial(d+n/d-1, d).

Terms

a(0) =1a(1) =1a(2) =4a(3) =0a(4) =6a(5) =3a(6) =8a(7) =-8a(8) =20a(9) =0a(10) =12a(11) =-12a(12) =14a(13) =-7a(14) =72a(15) =-65a(16) =18a(17) =10a(18) =20a(19) =-61a(20) =142a(21) =-33a(22) =24a(23) =-203a(24) =152a(25) =-52a(26) =248a(27) =-183a(28) =30a(29) =121