SMO 2011 Junior Round 1 Question 8
SMO · SMO 2011 Junior Round 1
Let $n=(2^4-1)(3^6-1)(5^{10}-1)(7^{12}-1)$. Which of the following statements is true?
$n$ is divisible by 5, 7 and 11 but not 13.
$n$ is divisible by 5, 7 and 13 but not 11.
$n$ is divisible by 5, 11 and 13 but not 7.
$n$ is divisible by 7, 11 and 13 but not 5.
None of the above.