OFFSET

1,6

LINKS

G. Brinkmann, J. Goedgebeur and B. D. McKay, snarkhunter.

EXAMPLE

For n=5, the unique 10-node cubic graph that is strictly 1-connected is:

o o

/|\ /|\

o-o o-o o-o

\|/ \|/

o o

PROG

(nauty) # The snarkhunter program (see Links) has an option "C2" for (at least) 2-connectivity. So a(n) is the difference between the outputs from "./snarkhunter X 3 ns" and "./snarkhunter X 3 ns C2", where X=2n.

CROSSREFS

KEYWORD

nonn,more

AUTHOR

Ed Wynn, Jul 22 2023

STATUS

approved