It has not been resolved. The only other post I received was from Kai Ohlhus who tried it in both Octave and Matlab with the same error. He opined that SpiralNumbering was missing and suggested I contact the author. It is clearly not a built-in Matlab function and so I am stuck. The author Daniël Karssen has done quite a lot of work in this area on 0EIS. I have looked at his other contributions to see if he has used it elsewhere. I have not found it. I have no contact details for him and he has not left anyway to contact him in OEIS. I know that programmers are not keen to try and modify someone else's program but I'm guessing that the missing module puts numbers in squares surrounding the knight from the knight's last position. I'm not quite sure how to do that quite apart from having no Matlab experience. So if there' is any light that you can throw on this it will be very welcome. I run a local Mathsjam group in Bexhill and Knight's Tours have been a topic of conversation from time to time. One of our members was George Jellis who is probably the world expert on Knight's Tours but he had not come across this version. I hope to talk about this new problem at our next Mathsjam on 19th February. Whilst I am quite familiar with Knights tours and even played with them as a child when I found out about this particular problem on the Numberphile video I paused it to think about what the likely outcome would be. It seemed to me that given an infinite board and the ability the knight to move to any one of eight squares that it would make a pretty pattern that would go to infinity. So it was a surprise that this is not the case. So if there's any light you can throw on this to get the code going then please let me know.
And I have written a function that if you give it a location in that array it finds the eight possible
knight move locations, and returns the smallest spiral number's location.
We still have to keep track of the location that have been visited, etc.
Are you interested in these. I will add some comments.
PS keep Octave help in the loop.