OFFSET
3,3
COMMENTS
A graph is uniquely 3-colorable if there is a unique partition of its vertex set into 3 independent sets. This implies that every proper 3-coloring of the graph has this partition as its set of color classes.
FORMULA
a(n) = A369227(n,3). - Eric W. Weisstein, Jan 16 2024
EXAMPLE
a(3) = 1 and a(4) = 1 because the complete graph K3 and K4-e are the only such graphs on 3 and 4 vertices, respectively.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Gordon Royle, Oct 08 2021
STATUS
approved