Ed Pegg Jr. writes: << Joe Kisenwether has upped the ante. Arrange the numbers 1-32 in a circle so that any two adjacent numbers sum to a square number. The answer is unique.

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That's an interesting circle. I'd like to see a picture of the circle of numbers 1-32 in numerical order, with 32 chords indicating adjacency in the Kisenwether ordering -- especially with that ordering being unique. --Dan