7

This number is a prime.

Just showing those entries submitted by 'Homewood': (Click here to show all)

7! + 6! - 5! + 4! - 3! + 2! - 1! and 7! - 6! + 5! - 4! + 3! - 2! + 1! are each members of a twin prime pair! [Homewood]

There are 7 sexy prime quadruplets up to a thousand. [Homewood]

Why is 10 afraid of 7? Because 7 8 9 and 10 is next! [Homewood]

The only prime heptagonal number. [Homewood]

The only twin prime of the form 30n-23. [Homewood]

Mark Spitz set an Olympic record in 1972 by winning 7 gold medals. [Homewood]

In a list of numbers of the form 3n + 1, starting with n = 0, the Mersenne primes have a Wagstaff prime index. [Homewood]

The opposite faces on a dice add up to 7, i.e., 6 + 1, 2 + 5 and 3 + 4. [Homewood]