Has here been any work done to find out about the average HN user? It seems like it would be a hard thing to do but it might be interesting to see. I do not even know what sort of metrics would be useful to measure.
There's certainly a strong element of computational mathematics. A lot of the problems deal with things like Mersenne Primes or Collatz sequences. On the other hand, there are problems like "Maximum Path Sum" which definitely make use of DSA-style tricks (https://projecteuler.net/problem=67).