Newsgroups: rec.puzzles
From: hoey@ai.etl.army.mil (Dan Hoey)
Date: 19 Dec 90 14:00:20 GMT
Subject: A new and better digit puzzle

How many 9-digit primes have 9 different digits?

For each digit d, how many of the primes contain all digits but d?

Can you explain the distribution, at least approximately?

What happens if we extend the problem to include 8-digit primes with a
leading zero (which then must not occur in tne other 8 digits)?

What about bases 3 through 16, say, or more?  In each case we ask for
a base B number with B-1 distinct digits.

Fans of extremely short limericks may be interested in considering the
case for B<3, but I don't want to hear the answers.

Dan Hoey
Hoey@AIC.NRL.Navy.Mil