L.g.f.: Sum_{n>=1} (x^n/n) * Product_{d|n} (1 + n*x^d/d).

Terms

a(0) =1a(1) =3a(2) =4a(3) =7a(4) =11a(5) =12a(6) =29a(7) =15a(8) =49a(9) =43a(10) =100a(11) =100a(12) =157a(13) =45a(14) =299a(15) =159a(16) =273a(17) =795a(18) =761a(19) =307a(20) =830a(21) =2126a(22) =1657a(23) =3276a(24) =1711a(25) =965a(26) =3505a(27) =6405a(28) =1509a(29) =9967