Maths Olympiad Prep

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Number theory Difficulty 4.6 AIME Find the answer

Let nn be the second smallest integer that can be written as the sum of two positive cubes in two different ways. Compute nn.

A number or a short expression. Spacing and $ signs are ignored.

Solution

A computer search yields that the second smallest number is 4104 . Indeed, 4104=93+153=23+1634104=9^{3}+15^{3}=2^{3}+16^{3}

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