# Definition:Woodall Prime/Sequence

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## Sequence

The sequence $\sequence n$ for which $n \times 2^n - 1$ is a prime number begins:

- $2, 3, 6, 30, 75, 81, 115, 123, 249, 362, 384, 462, 512, 751, \ldots$

This sequence is A002234 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).

The first few of these correspond with the sequence $\sequence n$ of the actual Woodall primes themselves, which begins:

- $7, 23, 383, 32212254719, 2833419889721787128217599, 195845982777569926302400511, \ldots$

This sequence is A050918 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).

## Sources

- 1986: David Wells:
*Curious and Interesting Numbers*... (previous) ... (next): $141$ - 1997: David Wells:
*Curious and Interesting Numbers*(2nd ed.) ... (previous) ... (next): $141$

- Weisstein, Eric W. "Woodall Number." From
*MathWorld*--A Wolfram Web Resource. http://mathworld.wolfram.com/WoodallNumber.html