G.f.: exp( Sum_{n>=1} (x^n/n) / Product_{d|n} (1 - d*x^n) ).

Terms

a(0) =1a(1) =1a(2) =2a(3) =3a(4) =6a(5) =8a(6) =17a(7) =22a(8) =44a(9) =62a(10) =115a(11) =154a(12) =311a(13) =409a(14) =754a(15) =1070a(16) =1949a(17) =2639a(18) =4917a(19) =6645a(20) =12055a(21) =16916a(22) =29594a(23) =40719a(24) =73907a(25) =100959a(26) =176010a(27) =248207a(28) =429626a(29) =594220