a(n) = Sum_{d|n} d*binomial(n/d+d-2,d-1).

Terms

a(0) =1a(1) =3a(2) =4a(3) =9a(4) =6a(5) =22a(6) =8a(7) =33a(8) =28a(9) =46a(10) =12a(11) =131a(12) =14a(13) =78a(14) =136a(15) =177a(16) =18a(17) =307a(18) =20a(19) =456a(20) =302a(21) =166a(22) =24a(23) =1149a(24) =376a(25) =222a(26) =568a(27) =1177a(28) =30a(29) =2387