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

Terms

a(0) =1a(1) =3a(2) =10a(3) =3a(4) =26a(5) =13a(6) =50a(7) =-177a(8) =352a(9) =-84a(10) =122a(11) =-996a(12) =170a(13) =-153a(14) =9704a(15) =-13313a(16) =290a(17) =-6518a(18) =362a(19) =-2771a(20) =107986a(21) =17073a(22) =530a(23) =-805070a(24) =394376a(25) =99984a(26) =1203580a(27) =1196313a(28) =842a(29) =-4500745