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A351160 Number of polyominoes of 2n cells with both diagonal symmetries, for which the 180-degree rotational symmetry has an axis that coincides with a vertex of a square, but without 90-degree rotational symmetry. 2
0, 0, 0, 1, 1, 2, 4, 10, 14, 37, 55, 142, 208, 531, 792, 2015 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

This sequence enumerates a subset of the polyominoes enumerated by A056878.

LINKS

Table of n, a(n) for n=1..16.

FORMULA

a(n) = A056878(2*n) - A351159(2*n).

EXAMPLE

a(4)=1 because of:

O

OOO

OOO

O

CROSSREFS

Cf. A000105, A056878, A351159.

Sequence in context: A082230 A236547 A078775 * A056392 A080149 A217134

Adjacent sequences: A351157 A351158 A351159 * A351161 A351162 A351163

KEYWORD

nonn,more

AUTHOR

John Mason, Feb 03 2022

STATUS

approved

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Last modified February 1 03:56 EST 2023. Contains 359981 sequences. (Running on oeis4.)