|
|
A289137
|
|
Number of extended polydrafters with n cells, identifying mirror images.
|
|
2
|
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
An extended polydrafter is a plane figure formed by joining congruent 30-60-90 triangles along edges and half hypotenuses, without the requirement for proper polydrafters that the cells lie on the polyiamond (triangle) grid.
|
|
LINKS
|
|
|
EXAMPLE
|
a(2)=13 because there are 6 proper didrafters and 7 more didrafters that do not conform to the polyiamond grid.
See the Logelium link for diagrams.
|
|
CROSSREFS
|
Cf. A056842 (number of [proper] polydrafters with n cells); A217720 (number of one-sided polydrafters with n cells).
|
|
KEYWORD
|
nonn,more,hard
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|