Recently I posted a question about tiling dominoes in a 3x10 area. The community arbitrarily decided my puzzle is off-topic because it's "too mathy". Yet, questions like
- Keys and Locks Puzzle
- What do 84, 96 and 108 have in common?
- Longest subsequences and shortest longest ones
- Visiting all strings by swapping
- Anything tagged with formation-of-numbers, which end up being brute-force anyway
- Anything tagged combinatorics
- Most puzzles tagged tiling
- A table filled with greatest common divisors, which requires computation with the Dirichlet hyperbola method, a technique pretty much limited to number theorists and competition programmers
are received perfectly well, even though most are combinatorial or computational in nature. I believe I've been on Stack Exchange long enough to know why this is happening. Sadly it is because I have only accumulated 700 rep on this SE while all those other questions are asked by 10k+ rep users. When I was low-rep on PPCG and SO I was treated the same way, but now that I have 10k+ rep they apply a different standard. The other reason is the "bandwagon effect" where one user who decides he doesn't think a puzzle is puzzle-enough puts in a close-vote and others follow along without thinking about the standard.
The tour page says "no textbook math problems". If my question appears in some combinatorics textbook, then the GCD question is even more cut-and-dry application of the Dirichlet Hyperbola method. The Keys and Locks puzzle is an application of a theorem in a graph theory textbook. The visiting all strings by swapping is a textbook application of graph theory. Is my question too easy? Should I just pick a question from a harder textbook? How about any of the later questions from Stanley's Enumerative Combinatorics just because they're hard? Peter Taylor points out in xnor's criteria on what is a puzzle or not that at least half of his examples are textbook problems. If the criteria is there has to be a "trick", well my question does have a nice trick and it's not brute-forcing every possibility.