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A Cullen number is a positive integer of the form:
- $n \times 2^n + 1$
- $1, 3, 9, 25, 65, 161, 385, \ldots$
corresponding to $n = 0, 1, 2, 3, \ldots$
Also defined as
Some sources refer to numbers of the form $n \times 2^n - 1$ as also being Cullen numbers.
Also known as
Source of Name
This entry was named for James Cullen.
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $141$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $141$