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

Terms

a(0) =1a(1) =5a(2) =10a(3) =29a(4) =26a(5) =123a(6) =50a(7) =305a(8) =352a(9) =668a(10) =122a(11) =3844a(12) =170a(13) =2593a(14) =9704a(15) =13825a(16) =290a(17) =41598a(18) =362a(19) =118259a(20) =107986a(21) =33047a(22) =530a(23) =929102a(24) =394376a(25) =130744a(26) =1203580a(27) =2737415a(28) =842a(29) =9910225