OFFSET
1,1
COMMENTS
Other sparse rulers in the range length 1 to 213 have round(sqrt(9 + 12*k)/2) minimal marks.
Minimal vertices in k-edge graceful graph = minimal marks in length k sparse ruler.
Conjecture: Minimal marks k - round(sqrt(9 + 12*k)/2) is always 0 or 1.
LINKS
P. Luschny, The Perfect Ruler Pyramid (1-101)
P. Luschny, Perfect and Optimal Rulers
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
Ed Pegg Jr, Jun 23 2019
STATUS
approved