+140 Let \(f(n)\) return the number of distinct ordered pairs of positive integers \((a,b)\) such that for each ordered pair, \(a^2 + b^2 = n\). Note that when \(a \neq b\), \((a, b)\), and \((b, a)\) are distinct. What is the smallest positive integer \(n\) for which \(f(n) = 3\).
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