A365655 - OEIS

A365655

Number of fixed n-polyominoids, allowing right-angled connections only ("hard" polyominoids).

3, 12, 68, 438, 3054, 22417, 170610, 1334316

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OFFSET

1,1

COMMENTS

Apparently, the definition of "hard" polyominoid in the Wikipedia article differs from the definition used here. Here, two squares are allowed to meet in a straight 180-degree connection provided that the structure be connected through right-angled ("hard") connections only; see A365654 for further details.

LINKS

Table of n, a(n) for n=1..8.

Wikipedia, Polyominoid.

Index entries for sequences related to polyominoes.

CROSSREFS

Cf. A075678 (polyominoids), A365654 (free).

13th and 17th row of A366767.

Sequence in context: A187118 A121812 A039750 * A366228 A296979 A004127

Adjacent sequences: A365652 A365653 A365654 * A365656 A365657 A365658

KEYWORD

nonn,hard,more

AUTHOR

Pontus von Brömssen, Sep 17 2023

STATUS

approved