+248 The function $f (n) = n^2 + n + 17$ for $0 \leq n \leq 15$ generates prime numbers. What is the value of $f (10)-f (9)$?
+113 \(f(n) = n^2 + n + 17\)
\(f(10) = 10^2 + 10 + 17 = 100 + 10 + 17 = 127\)
\(f(9) = 9^2 + 9 + 17 = 81 + 9 + 17 = 107\)
\(f(10) - f(9) = 127 - 107 = 20\)
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