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

Terms

a(0) =1a(1) =2a(2) =2a(3) =4a(4) =2a(5) =8a(6) =2a(7) =10a(8) =8a(9) =12a(10) =2a(11) =34a(12) =2a(13) =16a(14) =32a(15) =38a(16) =2a(17) =62a(18) =2a(19) =92a(20) =58a(21) =24a(22) =2a(23) =210a(24) =72a(25) =28a(26) =92a(27) =198a(28) =2a(29) =394