+152
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 \(f(n) = 3\)?
+26393 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 \(f(n) = 3\)?
The smallest positive integer n = 50.
\(f(50) = 3 : \\ \quad 1^2 + 7^2 = 50 \\ \quad 5^2 + 5^2 = 50 \\ \quad 7^2 + 1^2 = 50\)
the next:
\(f(200) = 3: \\ \quad 2^2 + 14^2 = 200 \\ \quad 10^2 + 10^2 = 200 \\ \quad 14^2 + 2^2 = 200 \)
the next:
\(f(338) = 3: \\ \quad 7^2 + 17^2 = 338 \\ \quad 13^2 + 13^2 = 338 \\ \quad 17^2 + 7^2 = 338 \)
the next:
\(f(450) = 3: \\ \quad 3^2 + 21^2 = 450 \\ \quad 15^2 + 15^2 = 450 \\ \quad 21^2 + 3^2 = 450\)
the next:
\(f(578) = 3: \\ \quad 7^2 + 23^2 = 578\\ \quad 17^2 + 17^2 = 578\\ \quad 23^2 + 7^2 = 578\)
the next:
\(f(800) = 3: \\ \quad 4^2 + 28^2 = 800 \\ \quad 20^2 + 20^2 = 800 \\ \quad 28^2 + 4^2 = 800\)
\(\ldots\)
