OFFSET
1,3
REFERENCES
Dumitrescu, Adrian; and Steiger, William; On a matching problem in the plane. Discrete Math. 211, No.1-3, 183-195 (2000). Zbl 0953.52009
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Dec 11 2011
EXTENSIONS
It is known that a(18)=14, a(20)=16.
STATUS
approved