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Wilfred Whiteside of Houston, Texas, discovered the following 7-by-7 array in which 281 primes can be found:

 3 1 3 7 3 3 9
 9 9 2 3 3 3 3
 6 9 7 7 8 9 4
 7 6 1 5 9 1 9
 7 7 3 4 2 1 1
 9 9 4 7 9 3 9
 3 3 7 1 9 9 9.

The largest prime p such that (1!+2!+3!+4!+ ... +p!) - 2 is prime. [Capelle]

281 is the sum of consecutive primes up to 43. If we add consecutive primes up to 281, it too is prime (7699). Note that there are no other such primes with this behavior between 281 and 7699. [Poo Sung]