Mark: thanks for the points. I first looked at solutions and ran my R program without imposing the constraint. The “smallest” in my answer is referring to , as this was the original question. It is true there are several solutions in . Actually, Le Monde asked for the smallest solution in with a unique solution in .

]]>Second, since there are 5 solutions with Y = 2016 (N = 168, 336, 504, 672, 840), why do you refer to (Y, N) = (2016, 504) as the smallest?

(I wrote a Mathematica program for brute-force checking.)

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