Better strategy for 235-problem

• What is the problem with brute force?
• The gaps between 235-numbers gets bigger as we go on...
  • 10 12 15 p235(n-1) p235(n)
• Most of the time is wasted in testing obviously wrong numbers?

Is there a need to test at all?

Can we only GENERATE numbers that have this property?

Compare with prime numbers problem.