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 2022-01-30, 10:37 #1 Mikloska   22·3·593 Posts "Not Mersenne" formula Dear colleagues! I made a mathematical formula to find large prime numbers. Are you interested? Last fiddled with by Dr Sardonicus on 2022-01-31 at 01:43
 2022-01-30, 13:05 #2 LaurV Romulan Interpreter     "name field" Jun 2011 Thailand 100111000111012 Posts No.
 2022-01-30, 13:08 #3 retina Undefined     "The unspeakable one" Jun 2006 My evil lair 2×3×1,093 Posts
2022-01-30, 13:57   #4
Dr Sardonicus

Feb 2017
Nowhere

589710 Posts

Quote:
 Originally Posted by Mikloska I made a mathematical formula to find large prime numbers. Are you interested?
No. This is not a real claim. You have failed to specify what you mean by the following:

"mathematical formula," "find," or "large."

There are any number of "mathematical formulas" for primes; see, e.g. here.

If, as per standard mathematical notation, pn denotes the nth prime, p10^1000000000 is a "large prime." Ta-daaaa!

 2022-01-30, 21:12 #5 ZFR     Feb 2008 Meath, Ireland 3·61 Posts f(x) = 1x+0x! What did I win?
2022-01-31, 00:17   #6
Dr Sardonicus

Feb 2017
Nowhere

170916 Posts

Quote:
 Originally Posted by ZFR f(x) = 1x+0x! What did I win?
No prize. Your formula yields the value 1 for x = positive integer, and 1 is not a prime. A prime number is greater than 1 by definition.

But I like your approach, so in the same spirit, I mention the time-honored

4 + (-1)n (n = positive integer)

and adapt it to yield the largest known pair of "twin primes" which should qualify as "large primes."

2996863034895*21290000 + (-1)n [Tom Greer, PrimeGrid, TwinGen, LLR 2016]

2022-01-31, 00:40   #7
paulunderwood

Sep 2002
Database er0rr

22×1,063 Posts

Quote:
 Originally Posted by Dr Sardonicus No prize. Your formula yields the value 1 for x = positive integer, and 1 is not a prime. A prime number is greater than 1 by definition.
I think ZFR meant (1^x)+((0^x)!)

See: https://en.wikipedia.org/wiki/Factor...torial_of_zero.

x=0 also holds, but it is undefined for x<0.

 2022-01-31, 00:45 #8 ZFR     Feb 2008 Meath, Ireland 3·61 Posts Yes, I meant 1 plus 0 factorial.
2022-01-31, 00:49   #9
ZFR

Feb 2008
Meath, Ireland

B716 Posts

Quote:
 Originally Posted by paulunderwood x=0 also holds
I was under the impression 0^0 is undefined. Looks like I was wrong.
https://en.m.wikipedia.org/wiki/Zero..._power_of_zero

This thread actually taught me something new.

2022-01-31, 01:10   #10
paulunderwood

Sep 2002
Database er0rr

22×1,063 Posts

Quote:
 Originally Posted by ZFR I was under the impression 0^0 is undefined. Looks like I was wrong. https://en.m.wikipedia.org/wiki/Zero..._power_of_zero
It seems to depend on what your field of mathematics is as to whether it is defined or not. We are on shaky ground here with this subject!

Last fiddled with by paulunderwood on 2022-01-31 at 01:11

2022-01-31, 01:32   #11
Dr Sardonicus

Feb 2017
Nowhere

5,897 Posts

Quote:
 Originally Posted by ZFR Yes, I meant 1 plus 0 factorial.
I apologize - I should have realized the exclamation point was the factorial symbol.

Your f(x) is 2 for positive integer x. That's prime, no question.

I don't know about a prize, but you get style points for expressing 1 as (0x)!

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