A hexagonal tile with number is surrounded by a ring of six hexagonal tiles, starting at "12 o'clock" and numbering the tiles to in an anti-clockwise direction.
New rings are added in the same fashion, with the next rings being numbered to , to , to , and so on. The diagram below shows the first three rings.
By finding the difference between tile and each of its six neighbours we shall define to be the number of those differences which are prime.
For example, working clockwise around tile the differences are , and . So .
In the same way, the differences around tile are , and , hence .
It can be shown that the maximum value of is .
If all of the tiles for which are listed in ascending order to form a sequence, the th tile would be .
Find the th tile in this sequence.
Write-up coming later
The complete problem is available here. An approach, code, and answer will be added later.