OFFSET
0,9
COMMENTS
Also called non-0-ubiquitous.
LINKS
Frank Van Bussel, 0-Centred and 0-ubiquitously graceful trees, Discrete Mathematics 277.1-3 (2004): 193-218. See Section 2.
EXAMPLE
For n=6 the tree with a-b-c-d-e
\
f
has no graceful solution with 'c' labeled as '0'.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Michael Arnold, Jun 15 2024
STATUS
approved