After the 23rd Mersenne prime was found at the University of Illinois, the mathematics department was so proud that the chair of their department, Dr. Bateman, had their postage meter changed to stamp “2^11213-1 is prime” on each envelope. This was used until the four color theorem was proved in 1976. (In 1985 Dr. Bateman printed several copies of the earlier imprint–the image on the left is from one of these.)
Het plaatje staat natuurlijk niet “on the left” hier, maar dat is de oorspronkelijke tekst.
Meer leeswaardigs op www.utm.edu/research/primes/mersenne/index.html