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

Terms

a(0) =1a(1) =3a(2) =5a(3) =9a(4) =9a(5) =22a(6) =13a(7) =32a(8) =35a(9) =53a(10) =21a(11) =121a(12) =25a(13) =96a(14) =177a(15) =166a(16) =33a(17) =297a(18) =37a(19) =491a(20) =417a(21) =218a(22) =45a(23) =1002a(24) =549a(25) =297a(26) =705a(27) =1375a(28) =57a(29) =2418