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A365655
Number of fixed n-polyominoids, allowing right-angled connections only ("hard" polyominoids).
5
3, 12, 68, 438, 3054, 22417, 170610, 1334316
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.
CROSSREFS
Cf. A075678 (polyominoids), A365654 (free).
13th and 17th row of A366767.
Sequence in context: A187118 A121812 A039750 * A366228 A296979 A004127
KEYWORD
nonn,hard,more
AUTHOR
STATUS
approved