Mondo Fuego™Did you know ...Mon Aug 14, 2017 5:26am68.114.135.59... the sum of the digits of a prime number is a prime number? It's the easy way to tell if a number is a prime number.

I just discovered this little-known fact on my own, although I am quite sure others have noticed the same thing.

Archimedes Spiral and Prime Numbers — Ex-News Junkie, Sun Aug 6 7:23pmBelow is a plot of 32,000 prime numbers on an Archimedes Spiral. In the first plot it just looks like an onion. In the second plot I hid the lines joining the points. All the points are prime numbers ... more

I cannot see any such diagram. (nm) — DFM, Tue Aug 29 12:31am

Photobucket no longer supports 3rd party hosting — Ex-News Junkie, Tue Aug 29 2:00pmfor free.

I use https://imgur.com/ — Ken C, Fri Sep 29 9:11pmI use https://imgur.com/ Example: I think it took them a whole 3 days — Ex-News Junkie, Tue Sep 12 7:08pmto notice my link before they wrecked it.

- Did you know ... — Mondo Fuego™ , Mon Aug 14 5:26am

Is 49 a prime number? (nm) — Ex-News Junkie, Tue Aug 15 8:28pm

No, it is 7 squared (nm) — jb, Tue Aug 22 2:17pm

Thanks Captain Obvious (nm) — Ex-News Junkie, Tue Aug 29 2:47pm

Drum roll — Ex-News Junkie, Tue Aug 8 3:19pmNot sure about the notation, but here goes: The set of all prime numbers P is a subset of SP: SP = {2,3,5, and R + n x 360}, for n = {0,1,2,3,... } where R = { 1,7,11,13,17,19,23,29,... more

Another variation — Ex-News Junkie, Tue Aug 8 7:31pmAll prime numbers P are a subset of SP = {2,3,5, and R + n x 30} where R = {1,7,11,13,17,19,23,29} n = {0,1,2,3,... } P is prime if (P mod SP) 0 It's simpler I suppose, but it loses the perspective... more

It's just a coincidence — Ex-News Junkie, Sat Aug 19 9:31pmIf you write the numbers out from 1 to 30, then cross out all the even numbers, then cross out any number that is divisible by 3,5,7 or 9, what remains are the root angles. You can plot the result in ... more

In fact it's even worse — Ex-News Junkie, Mon Sep 18 5:44pmIt is basically a plot of all odd numbers. The only reason they are prime numbers is because they've been checked beforehand to eliminate odd numbers that are multiples of smaller numbers. Every... more