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
