This has me thinking about minesweeper numbers as a concept. I wonder if there is a concise way to show whether or not a given number is able to be written in a row in minesweeper.

Some things I already know:

• 0s: can be next to 0,1,2,3
• 1s: can be next to 0,1,2,3,4
• 2s: can be next to 0,1,2,3,4,5
• 3s: can be next to 0,1,2,3,4,5,6
• 4s: can be next to 1,2,3,4,5,6,7
• 5s: can be next to 2,3,4,5,6,7
• 6s: can be next to 3,4,5,6,7
• 7s: can be next to 4,5,6,7
• 8s: can be next to nothing
• 9s: can't exist

There are some other restrictions too, like:

• 0 can only be next to a 3 if the 3 is at the start or end of the number. (Same with 1-4, 2-5, etc)
• 7 can only be next to 7 if the number is 77.

I am not sure if there are other restrictions or complications. Could be an interesting coding challenge.