Problem of the Month (June 2002)

This month we consider tilings of squares with consecutive squares. It is well known that the only non-trivial solution of 12 + 22 + . . . + n2 = k2 is n=24 and k=70. Unfortunately, it has been proved that a square of size 70 cannot be tiled with squares of sizes 1 through 24. (There is a packing without the square of size 7. Can you find it?)

It turns out there ARE tilings of squares by consecutive squares if we allow either 1 or 2 squares of each size. We such a tiling a diverse tiling. The smallest non-trivial diverse tiling of a square is the 20x20 square below:

What other diverse tilings of a square can you find? Are there many diverse tilings of rectangles? What's the largest one you can find?

I'll pay $10 for the first diverse square tiling where repeated squares don't touch. I'll also pay $10 for the first diverse square tiling that contains 1 square each of odd sizes and 2 squares each of even sizes. I'll also pay $10 for the first diverse tiling of a triangle by smaller equilateral triangles.


ANSWERS

Antonio Ianiero found diverse square tilings of sizes 1-10 in a 25x25 square, sizes 1-12 in a 30x30 square, and sizes 1-12 in a 33x33 square.

Patrick Hamlyn wrote a computer program to seach for diverse square tilings of certain sizes. He found that all diverse square tilings smaller than 48x48 have two equal squares that touch. His results are below:

Numbers of Diverse Square Tilings

nNumber of Diverse Tilings of nxn Square
11
201
231
251
261
2992
30?
31?
32?
33?
3466
35276
36136
37422
3862

Here are some small diverse square tilings:

Diverse Square Tilings

nSizes of Square
11
920, 23
1025, 26
1129
1229, 30, 31, 32, 33
1334, 35, 36
1435, 36, 37, 38

And here are some small non-square diverse rectangle tilings:

Diverse Rectangle Tilings

nRectangles
12x1
23x2, 5x2
35x3, 8x3
48x7
59x8
817x15, 18x15, 28x14
921x15, 24x14, 24x18, 26x15, 30x14
1026x22, 27x23, 28x22, 30x20, 32x16, 36x15, 36x19, 42x14
1129x21, 30x25, 30x26, 30x29, 31x27, 31x30, 37x22, 39x22

If you can extend any of these results, please e-mail me. Click here to go back to Math Magic. Last updated 7/28/02.