There are 168 primes less than 1,000. What is the sum of the prime numbers less than 1,000?
(a) 11,555 (b) 76,127 (c) 57,298 (d) 81,722
Find the sum of all the prime numbers larger than 2 less than 10^12 that are 1 more than a perfect square. Because the number can get pretty big provide the answer mod 1007.
Note: Problem shouldn't take much more than one minute if your answer is taking too long consider looking for optimizations.
Four different prime numbers 5, 7, 17 and 19 such that the sum of any three of them is also a prime. Are there 5 different positive primes such that the sum of any three of them is also a prime?
