Deletion of Determination of the day of the week

Comment: basically per what Mark viking said. The whole field of algorithms is "how to"; that doesn't make descriptions of notable algorithmic problems off-topic for Wikipedia.  is misapplied in this case: it's more aimed at keeping out game walkthroughs, troubleshooting guides, and recipes than descriptions of mathematical algorithms. And in this case, the attention to this specific problem given by such famous mathematicians as Charles Dodgson and John Conway makes it clearly notable
Stance: keep
Cited policy: Wikipedia:What Wikipedia is not (WP:NOTHOWTO)