244
xkcd #2937: Room Code
(imgs.xkcd.com)
Alt text:
Sorry to make you memorize this random string of digits. If it helps, it can also double as a mnemonic for remembering your young relatives' birthdays, if they happened to have been born on February 5th, 2018.
The second half is 3 digits. I'd just hard code memorize it.
The first half is something between 0. It's a easy pattern.
The last missing digit must be something simple and deductible from other numbers if I put it to the last. As all other numbers (
0,518) are even, it should be2.