Did you solve it? The count reaches 'twenty, twenty-one'
by Alex Bellos from Science | The Guardian on (#5C5E3)
The answers to today's puzzles
Earlier today I set you three puzzles concerning the number 2021, which is the concatenation of two consecutive integers, 20 and 21. Before we get to the problems (and the answers), thanks to reader ConradKnightSocks for alerting me to the brilliant fact that 2021 is also the product of two consecutive prime numbers: 43 x 47.
The last time this was the case was 1763, which is 41 x 43.
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