Number of aperiodic relatively prime trees with n nodes.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =4a(5) =10a(6) =20a(7) =48a(8) =108a(9) =255a(10) =595a(11) =1435a(12) =3434a(13) =8372a(14) =20419a(15) =50289a(16) =124289a(17) =309122a(18) =771508a(19) =1934462