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A319324
a(n) is the number of fixed polyglasses (polyiamonds which need only touch at corners) with n cells.
4
2, 12, 88, 710, 6054, 53500, 484784, 4475010, 41902626, 396838992, 3793117200, 36534684066
OFFSET
1,1
COMMENTS
Polyglasses are to polyiamonds (A001420) as polyplets (A006770) are to polyominoes (A001168). The name derives from the 2-celled animal (diglass) which looks like an hourglass.
LINKS
Rebecca M. Bowen, Sadie Pruitt, and Douglas A. Torrance, Properties of regular Tangles, arXiv:2405.20793 [math.CO], 2024. See p. 2.
EXAMPLE
a(2) = 12: three rotations of a diamond, three rotations of an hourglass and six rotations of "two mountains".
CROSSREFS
Cf. A001420 (fixed polyiamonds), A319325 (row convex polyglasses), A319326 (column convex polyglasses).
Sequence in context: A193125 A305868 A356830 * A059435 A192621 A372090
KEYWORD
nonn,more,hard
AUTHOR
David Bevan, Sep 18 2018
EXTENSIONS
a(12) from Aaron N. Siegel, May 22 2022
STATUS
approved