# 700 Followers prob!

Let $$f(x) = \sqrt{1^{2} + 2^{2} + 3^{2} + \cdots + (x-1)^{2} + x^{2}}$$.

Find the minimum value of $$n \geq2$$ such that $$f(n)$$ is a positive integer.

$$n$$ is a positive integer.

Clarification: $$f(x)$$ denote the square root of the sum of the squares of first $$x$$ positive integers.

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