MathDB
2016 LMT Individual #6

Source:

April 10, 2016
number theoryprime numbers

Problem Statement

A positive integer is called cool if it can be expressed in the form a!⋅b!+315a!\cdot b!+315 where a,ba,b are positive integers. For example, 1!⋅1!+315=3161!\cdot 1!+315=316 is a cool number. Find the sum of all cool numbers that are also prime numbers.
Proposed by Evan Fang
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