OFFSET
1,3
LINKS
Erich Friedman, Math Magic (September 2012)
EXAMPLE
A graph on 4 vertices can have either 0, 1 or 3 Hamiltonian cycles (up to direction), which are 3 numbers, so a(4)= 3.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Johan de Ruiter, May 27 2018
STATUS
approved