I remember as a youth reading about the largest known prime in the Guiness Book of World Records. The book was first published in 1955, I was born in 1960, and 2^11213-1 seems to have been the record prime between 1963 and 1971. With 3,376 digits, it would have easily fit on a page. To put this in perspective, I just downloaded a file containing the digits of 7,235,733 digits of 2^24036583, the recently-discovered current largest known prime. The enormity of these numbers sometimes does not register. Out of curiosity, I checked to see what is the smallest number which is not a substring of this new prime's digits, and it was 101679. - David W. Wilson "Truth is just truth -- You can't have opinions about the truth." - Peter Schickele, from P.D.Q. Bach's oratorio "The Seasonings"