Enumerating all 3-tuples

[Skip Montanaro]

>>> 4 (0, 0, 1)
>>> 9 (0, 0, 1)
>>> 18 (0, 0, 2)
>>> 32 (0, 0, 2)
>
> I spy duplicates.

I didn't realize we'd started playing "I Spy
<https://books.google.com/books/about/I_Spy.html?id=oxEQGwAACAAJ&source=kp_cover>
."
​ <wink>​

Skip