April 2019 - Solution

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April 2019 Challenge

One can solve for the same prime average for all rows, columns, and diagonals. For example:

 17 89  71
113 59   5
 47 29 101

Another general solution that also works for larger squares is to find an arithmetic progression of prime numbers and build a regular magic square.

Lorenz Reichel sent us a solution in which all the secondary diagonals also have prime averages:

73 43 61
31 79 19
37  7 97

Jingran Lin found nine different prime numbers that *every* triplet of them averages to a prime number:[440377009, 1109655619, 1206997621, 1371035311, 1778934229, 2448212839, 3117491449, 3786770059, 4456048669]

Thanks also to Marcelo M De Barros for his blog post on the challenge.