OFFSET
1,4
COMMENTS
Hand calculated by grade 3 students up to term 6: (1,1,1,3,5,12...)
EXAMPLE
a(5) = 5: A001433 tells us that there are 6 simple graphs with 5 vertices and 4 edges. Only 5 of these can be labeled gracefully. The one that cannot is the triangular loop plus two connected nodes: ∆ / .
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Gordon Hamilton, May 28 2014
STATUS
approved