Frank Nelson Cole, a professor of mathematics at Columbia University in New York, stood up at the American Mathematical Society conference, went to the blackboard, and without saying a word wrote: 2^67 – 1 = 193707721 * 761838257287, and returned to his seat. After a few moments, the audience of mathematicians was astonished and applauded for several minutes. It had taken him three years of Sunday afternoons to complete the calculation.
