Advent calendar 2018
6 December
![This puzzle was part of the 2018 Advent calendar.](/img/advent/2018-advent-banner.png)
This puzzle is inspired by a puzzle that Daniel Griller showed me.
Write down the numbers from 12 to 22 (including 12 and 22). Under each number, write down its largest odd factor*.
Today's number is the sum of all these odd factors.
* If a number is odd, then its largest odd factor is the number itself.