A240120 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has reflective symmetry in both diagonals and no other reflective symmetries.

0, 0, 0, 1, 1, 9, 19, 121, 275, 2489, 7217, 86775

Offset

1,6

Comments

'Inequivalent' has the same sense as in A224239: we do not regard dissections that differ by a rotation and/or reflection as distinct.

The two reflective symmetries imply 180-degree (but not 90-degree) rotational symmetry.

Links

Table of n, a(n) for n=1..12.

Ed Wynn, Exhaustive generation of Mrs Perkins's quilt square dissections for low orders, arXiv:1308.5420

Example

This is the single dissection for n=4:
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|   | | |
|   -----
|   | | |
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| | |   |
-----   |
| | |   |
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Crossrefs

Cf. A226979, A045846, A224239, A240121, A240122.

Sequence in context: A068174 A165247 A177130 * A177179 A335782 A041677

Adjacent sequences: A240117 A240118 A240119 * A240121 A240122 A240123

Keyword

nonn,more

Author

Ed Wynn, Apr 01 2014

Status

approved