All the squares on a chessboard

How many squares of all sizes (1×11\times1 up to 8×88\times8) can be found on a standard 8×88\times 8 chessboard?

Show hints (2)+
  1. How many k×kk\times k squares fit? Their top-left corner has (9k)2(9-k)^2 placements.
  2. k=18(9k)2=j=18j2=204\sum_{k=1}^8 (9-k)^2=\sum_{j=1}^8 j^2=204.

Answer

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204

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Asked at: Jane Street, Two Sigma

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