September 12


Care for a little recreational computing? Know how to compile (javac Primes.java) and run (java Primes) Java? Here’s a little tool that finds and shows the prime factors of a number. A few “interesting” numbers:

  • 9223372036854775807 - the largest number the program can handle (2^63-1)
  • 2286236833561957 - a number with prime factors greater than the one millionth prime (you can specify the size of the table of primes that the program uses)
  • 614889782588491410 - try it

posted @ 01:52 AM EDT

September 16

Primes Compiled

By popular demand, for those who don’t do Java development, here’s the compiled Primes.java code previously posted. To use it, run your favorite shell (known anachronistically in Windows as the “Command Prompt”) and get to the directory where you saved the class file. Then enter a command such as:

java -cp . Primes 614889782588491410 

posted @ 04:33 PM EDT

September 17

Wallis - Pawtuckaway 100 km Map

A couple of years ago I posted a cue sheet for a local metric century bike ride. Now I’ve created a Google map of the route. Thanks to the Charles River Wheelmen for showing this usage.

posted @ 09:24 AM EDT