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PROJECT EULER · #0126

Cuboid Layers

Statement only · SolvedOriginal problem ↗

The minimum number of cubes to cover every visible face on a cuboid measuring 3×2×1 is twenty-two.


If we then add a second layer to this solid it would require forty-six cubes to cover every visible face, the third layer would require seventy-eight cubes, and the fourth layer would require one-hundred and eighteen cubes to cover every visible face.

However, the first layer on a cuboid measuring 5×1×1 also requires twenty-two cubes; similarly the first layer on cuboids measuring 5×3×1, 7×2×1, and 11×1×1 all contain forty-six cubes.

We shall define C(n) to represent the number of cuboids that contain n cubes in one of its layers. So C(22)=2, C(46)=4, C(78)=5, and C(118)=8.

It turns out that 154 is the least value of n for which C(n)=10.

Find the least value of n for which C(n)=1000.

Write-up coming later

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