Searching I just found the following blog entry with similar calculations about optimal tire pressure:

Bike Tinker: Optimal Tire Pressure for Bicycles

Using the spreadsheet provided there, for a 170 lbs bike + rider weight and 23s, the rear tire would require 104 PSI and the front 67 PSI. Here's one of the charts in that blog -- in this one you need to check the wheel load against the PSI (they assume about 60% of the rider's weight + bike weight is carried by the rear wheel):



Again, I would take this as guidance only, since tires, roads and even riding styles can be different.