Number of rooted toroidal maps with 2 faces and n vertices and without separating cycles or isthmuses.

A006422

Number of rooted toroidal maps with 2 faces and n vertices and without separating cycles or isthmuses.

Terms

    a(0) =4a(1) =47a(2) =240a(3) =831a(4) =2282a(5) =5362a(6) =11256a(7) =21690a(8) =39072a(9) =66649a(10) =108680a(11) =170625a(12) =259350a(13) =383348a(14) =552976a(15) =780708a(16) =1081404a(17) =1472595a(18) =1974784a(19) =2611763a(20) =3410946a(21) =4403718a(22) =5625800a(23) =7117630a(24) =8924760a(25) =11098269a(26) =13695192a(27) =16778965a(28) =20419886a(29) =24695592

External references