A307072 Number of simple connected graphs on n nodes with crossing number 1.

0, 0, 0, 0, 1, 11, 149, 3008, 71335, 1814021

Offset

1,6

Links

Table of n, a(n) for n=1..10.

Example

5-node: K_5.
6-node: includes K_{1,2,3}, (5-1)-lollipop, 2 X 3 queen, utility graph K_{3,3}.

Crossrefs

Cf. A307071 (not necessarily connected graphs).

Cf. A003094 (connected graphs with crossing number 0).

Sequence in context: A175635 A103544 A038141 * A142083 A205085 A068646

Adjacent sequences: A307069 A307070 A307071 * A307073 A307074 A307075

Keyword

nonn,more

Author

Eric W. Weisstein, Mar 22 2019

Extensions

a(9) from Eric W. Weisstein, Apr 17 2019

a(10) from Eric W. Weisstein, Apr 28 2019

Status

approved