Sunday Afternoon Maths LVII

 Posted on 2016-11-27 

Largest odd factors

Pick a number. Call it \(n\). Write down all the numbers from \(n+1\) to \(2n\) (inclusive). For example, if you picked 7, you would write:
Below each number, write down its largest odd factor. Add these factors up. What is the result? Why?

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Square factorials

Source: Woody at Maths Jam
Multiply together the first 100 factorials:
Find a number, \(n\), such that dividing this product by \(n!\) produces a square number.

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If you enjoyed these puzzles, check out Sunday Afternoon Maths LXVII,
puzzles about doubling, or a random puzzle.


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