A390199 - OEIS

A390199

a(n) is the number of concave n-celled polyominoes in the {4,5} tessellation of the hyperbolic plane.

0, 0, 0, 0, 0, 0, 1, 7, 63, 458, 3209, 21160, 135308, 843204, 5165292

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OFFSET

1,8

COMMENTS

Define a {4,5} polyomino as being concave if one of the "straight" lines that connects the centers of adjacent squares in the lattice enters the polyomino more than once.

This sequence was calculated in the context of a project in collaboration with Érika Roldán, and Rosemberg Toalá-Enríquez.

LINKS

Table of n, a(n) for n=1..15.

CROSSREFS

Cf. A119611.

Sequence in context: A043027 A165759 A166153 * A123009 A219058 A182603

Adjacent sequences: A390196 A390197 A390198 * A390200 A390201 A390202

KEYWORD

nonn,more

AUTHOR

John Mason, Nov 02 2025

STATUS

approved