Definition:Woodall Number

Definition
A Woodall number is a positive integer of the form:
 * $n \times 2^n - 1$

Also known as
Some sources refer to numbers of the form $n \times 2^n - 1$ as Cullen numbers, along with those of the form $n \times 2^n + 1$.

However, it is now conventional to reserve the term Cullen numbers, named for, to those of the form $n \times 2^n + 1$.

The latter are also known as Cunningham numbers, for, so as to ensure their unambiguous distinction from Woodall numbers.

Also see

 * Definition:Woodall Prime