In 1644, French cleric and mathematician Marin Mersenne (1588–1648) proposed that the numbers 2n – 1 are prime for the values n = 2, 3, 5, 7, 13, 17, 19, 31, 67, 127, and 257, and they are composite for all other positive integers greater than 257. A prime is a whole number evenly divisible only by itself and 1.
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