A240123 - OEIS

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A240123

Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has a reflective symmetry in one diagonal, but no other symmetries.

0, 0, 1, 3, 19, 107, 847, 8647, 119835, 2255123, 58125783, 2050662011

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OFFSET

1,4

COMMENTS

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

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

The three dissections for n=4:

--------- --------- ---------

| | | | | | | | | |

| ----- | | | | ---

| | | | | | | | | |

--------- --------- | ---

| | | | | | | | | | | |

--------- | ----- ---------

| | | | | | | | | | | | | |

--------- --------- ---------

CROSSREFS

Cf. A226980, A045846, A224239, A240124, A240125.

Sequence in context: A089164 A323290 A072950 * A130425 A334976 A103005

Adjacent sequences: A240120 A240121 A240122 * A240124 A240125 A240126

KEYWORD

nonn,more

AUTHOR

Ed Wynn, Apr 01 2014

STATUS

approved