login
A066931
Number of ways to tile hexagon of edge n with diamonds of side 1, not counting rotations and reflections as different.
2
1, 1, 6, 113, 20174, 22306955, 123222909271, 3283834214485890, 421263391026827547540, 260028731850596651411721718, 772086476515163830856527013278243, 11025620741283840573496993339545350520150, 757129347300072898736973484532998417574513923224
OFFSET
0,3
LINKS
R. K. Guy and D. J. Reble, Illustration of initial terms
P. J. Taylor, Counting distinct dimer hex tilings, Preprint, 2015.
FORMULA
From Peter J. Taylor, Jun 17 2015: (Start)
For odd n, a(n) = A008793(n)/12 + A049505(n)/4 + A006366(n)/6.
For even n, a(n) = A008793(n)/12 + A049505(n)/4 + A006366(n)/6 + A181119(n/2)/4 + A259049(n/2)/12 + A049503(n/2)/6.
See Taylor link.
(End)
CROSSREFS
Cf. A008793.
Sequence in context: A275924 A288561 A291917 * A324669 A051228 A194132
KEYWORD
nonn
AUTHOR
R. K. Guy, Feb 05 2002
EXTENSIONS
One more term from Don Reble, Feb 07 2002
More terms from Peter J. Taylor, Jun 17 2015
STATUS
approved