1,6

a(n) <= A145269(n).

a(n) = A145269(n) for n < 8.

a(8) = A145269(8) - 15 since there are 15 double-toroidal graphs on 8 nodes (all of which are connected).

Table of n, a(n) for n=1..8.

Eric Weisstein's World of Mathematics, Simple Graph

Eric Weisstein's World of Mathematics, Toroidal Graph

Cf. A145269 (number of nonplanar simple graphs).

Sequence in context: A113894 A225315 A292041 * A145269 A221582 A320762

Adjacent sequences: A319111 A319112 A319113 * A319115 A319116 A319117

nonn,more

Eric W. Weisstein, Sep 10 2018

approved