On 2020-06-28 11:26 a.m., Doug McIlroy wrote:

I'm currently stuck on the Two Knights problem.

Having placed one knight on the board, in how many
places can you put the other?

If you check the website indicated, it's a slight variation on that:

"Your task is to count for $k = 1, 2, \dots, n$ the number of ways two knights can be placed on a $k \times k$ chessboard so that they do not attack each other."

The input is n (an integer that can range from 1 to 10000), the output is a single integer for each value from 1 to n, one per line, the memory limit is 512MB, and the maximum runtime is 1.00 seconds.