A Williams number is a natural number of the form (b-1)× bn-1 for integers b ≥ 2 and n > 1.
A Williams prime is a Williams number which is prime.
- H. C. Williams: "The primality of certain integers of the form 2Ar^n-1", Acta Arith. 39 (1981), 7-17.
- Williams number
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