10139 – Factovisors
Whee, factorization. My solution isn’t too exciting; half of it is copy and paste from the book, the other half is just understanding how to apply it.
10168 – Summation of Four Primes
So, the trivial solution is to use Goldbach’s conjecture after picking two easy numbers. Recursion is great that way. I started making the solution a bit more clever (see the hard-coded primes), but got lazy before I finished, so my solution is a bit of a mess.
10042 – Smith Numbers
So, I implemented this the naive way, just doing what the problem described, and the solution seemed to be fast enough. Win?