User talk:Paul Tek

Your contribution to A188428

Hello Professor Tek,

First off, thank you very much for expanding A188428! I was wondering if it would be possible to modify your PERL script to tackle this related problem: does there exist a string of length 152 on five symbols that contains all permutations of those five symbols as substrings (factors)?

My reason for asking this question is A180632. It is known that no such string of length 151 exists, and it is known that a string of length 153 does exist. However, the case of length 152 is unknown. I thought that this problem would be much too large to handle via computer search, but your excellent work on A188428 makes me think that maybe it is possible.

Nathaniel Johnston 01:24, 15 June 2013 (UTC)