Problem of the Week

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Semiprime

Posted: March 9, 2026

87 % of users got this correct

A positive integer is called semiprime if it is the product of two primes, not necessarily distinct. So both 4=2*2 and 6=2*3 are semiprime. Find the first prime P greater than 100 where P+1 is semiprime. Hence P is prime and P+1 is semiprime.

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