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# Sierpiński number base 5

A **Sierpiński number base 5** is a value of `k` such that `k`•5^{n}+1 is always composite.

Using the same method presented in the Sierpiński problem article, it was found that 159986•5^{n}+1 is multiple of 3, 7, 13, 31 or 601 (the covering set) depending on the value of `n`, so it is always composite.

In order to demonstrate whether 159,986 is the smallest Sierpiński number base 5 or not, a distributed computing project was created named Sierpiński-Riesel Base 5.