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A320945 a(n) is the number of top-perimeter tiles among all rhombic tilings of the 2n-gon. 2
1, 1, 3, 20, 268 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,3

COMMENTS

Also the number of bottom-perimeter tiles among all rhombic tilings of the 2n-gon. Tiles and polygons all have sides of length 1, as in A006245.

LINKS

Table of n, a(n) for n=2..6.

B. E. Tenner, Tiling-based models of perimeter and area, arXiv:1811.00082 [math.CO], 2018.

EXAMPLE

a(4) = 3 because among the eight rhombic tilings of the octagon, 3 top-perimeter rhombi appear.

CROSSREFS

Cf. A320944, A320946, A006245.

Sequence in context: A197975 A210906 A193194 * A166232 A136551 A266812

Adjacent sequences:  A320942 A320943 A320944 * A320946 A320947 A320948

KEYWORD

nonn,more

AUTHOR

Bridget Tenner, Oct 24 2018

STATUS

approved

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Last modified April 13 02:47 EDT 2021. Contains 342934 sequences. (Running on oeis4.)