Number of elementary graphs on n nodes.

Terms

a(0) =1a(1) =2a(2) =4a(3) =10a(4) =25a(5) =79a(6) =253a(7) =936a(8) =3601a(9) =15486a(10) =74413a(11) =441436a(12) =3505441a(13) =40309116a(14) =670660262