cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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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.

Original entry on oeis.org

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

Views

Author

Ed Wynn, Apr 01 2014

Keywords

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.

Examples

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

Crossrefs

A240121 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has two reflective symmetries in axes parallel to the sides, and no other reflective symmetries.

Original entry on oeis.org

0, 0, 0, 1, 0, 13, 5, 183, 75, 4408, 1501, 180324
Offset: 1

Views

Author

Ed Wynn, Apr 01 2014

Keywords

Comments

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

Examples

			This dissection is the only example for n=4:
---------
| |   | |
---   ---
| |   | |
---------
| |   | |
---   ---
| |   | |
---------
		

Crossrefs

A240122 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has 90-degree rotational symmetry and no reflective symmetry.

Original entry on oeis.org

0, 0, 0, 0, 1, 2, 12, 40, 154, 760, 3260, 22730
Offset: 1

Views

Author

Ed Wynn, Apr 01 2014

Keywords

Examples

			The two dissections for n=6:
-------------    -------------
| |   | | | |    | |   | | | |
---   -------    ---   -------
| |   | |   |    | |   | |   |
---------   |    ---------   |
| | |   |   |    | | | | |   |
-----   -----    -------------
|   |   | | |    |   | | | | |
|   ---------        ---------
|   | |   | |    |   | |   | |
-------   ---    -------   ---
| | | |   | |    | | | |   | |
-------------    -------------
		

Crossrefs

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.

Original entry on oeis.org

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

Views

Author

Ed Wynn, Apr 01 2014

Keywords

Comments

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

Examples

			The three dissections for n=4:
---------    ---------    ---------
|   | | |    |   |   |    |     | |
|   -----    |   |   |    |     ---
|   | | |    |   |   |    |     | |
---------    ---------    |     ---
| | | | |    |   | | |    |     | |
---------    |   -----    ---------
| | | | |    |   | | |    | | | | |
---------    ---------    ---------
		

Crossrefs

A240124 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has 180-degree rotational symmetry, but no other symmetries.

Original entry on oeis.org

0, 0, 0, 0, 2, 19, 109, 1781, 13660, 397689, 5368943, 289864745
Offset: 1

Views

Author

Ed Wynn, Apr 01 2014

Keywords

Examples

			The two dissections for n=5:
-----------    -----------
|   |   | |    | |   | | |
|   |   ---    ---   -----
|   |   | |    | |   | | |
-----------    -----------
| | | | | |    | | | | | |
-----------    -----------
| |   |   |    | | |   | |
---   |   |    -----   ---
| |   |   |    | | |   | |
-----------    -----------
		

Crossrefs

A240125 Number of inequivalent ways to cut an n X n square into squares with integer sides, such that the dissection has one reflective symmetry in an axis parallel to a side, but no other symmetries.

Original entry on oeis.org

0, 0, 0, 3, 5, 138, 201, 13032, 19990, 4095612, 7026883, 4451051502
Offset: 1

Views

Author

Ed Wynn, Apr 01 2014

Keywords

Examples

			The three dissections for n=4, with the axis horizontal:
---------    ---------    ---------
|   | | |    |   | | |    | | | | |
|   -----    |   -----    ---------
|   | | |    |   |   |    |   | | |
---------    -----   |    |   -----
|   | | |    |   |   |    |   | | |
|   -----    |   -----    ---------
|   | | |    |   | | |    | | | | |
---------    ---------    ---------
		

Crossrefs

A361524 Number of ways of dividing an n X n square into integer-sided rectangles, up to rotations and reflections.

Original entry on oeis.org

1, 1, 4, 54, 9235, 10538496, 66906507915, 2262572656817797, 406359897582963166777, 387240433077951047222490766, 1957233446631303872408683778546809, 52459774417987065589052845904624173777442, 7455958280198359250316552005822713102696893557376
Offset: 0

Views

Author

Pontus von Brömssen, Mar 15 2023

Keywords

Crossrefs

Main diagonal of A361523.
Cf. A182275 (rotations and reflections are considered distinct), A224239 (square pieces), A360630.

Programs

  • Python
    # See Jellis link.

Formula

a(n) >= A182275(n)/8.
a(n) ~ A182275(n)/8.

Extensions

a(6)-a(12) from Nathan Jellis, Aug 25 2025

A358716 a(n) is the number of inequivalent ways to cut an equilateral triangle with edges of size n into equilateral triangles with integer sides.

Original entry on oeis.org

1, 2, 3, 12, 50, 711, 18031, 952013, 92323440
Offset: 1

Views

Author

Craig Knecht and John Mason, Nov 28 2022

Keywords

Comments

Similar to A358715, but now we do not regard dissections which differ by a rotation and/or reflection as distinct.

Examples

			a(3)=3 because of:
    /\      /\      /\
   /  \    /\/\    /\/\
  /    \  /  \/\  /\/\/\
		

Crossrefs

A362259 Maximum number of ways in which a set of integer-sided squares can tile an n X n square, up to rotations and reflections.

Original entry on oeis.org

1, 1, 1, 1, 4, 20, 277, 7855, 487662
Offset: 0

Views

Author

Pontus von Brömssen, Apr 15 2023

Keywords

Crossrefs

Main diagonal of A362258.
Cf. A224239, A236679, A361222 (rectangular pieces), A362143.

Formula

a(n) >= A362143(n)/8.
Previous Showing 11-19 of 19 results.