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 A320946 a(n) is the number of left-perimeter tiles among all rhombic tilings of the 2n-gon. 2
 1, 2, 9, 80, 1340 (list; graph; refs; listen; history; text; internal format)
 OFFSET 2,2 COMMENTS Also the number of right-perimeter tiles among all rhombic tilings of the 2n-gon. Tiles and polygons all have sides of length 1, as in A006245. LINKS B. E. Tenner, Tiling-based models of perimeter and area, arXiv:1811.00082 [math.CO], 2018. FORMULA a(n) = (n-1) * A320945(n). EXAMPLE a(4) = 9 because among the eight rhombic tilings of the octagon, 9 left-perimeter rhombi appear. CROSSREFS Cf. A320944, A320945, A006245. Sequence in context: A109519 A193208 A279055 * A135868 A212271 A147302 Adjacent sequences:  A320943 A320944 A320945 * A320947 A320948 A320949 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.)