Is there a formula for finding the next prime number?

Answer 1

No there isn't. This is one of the big unsolved problems in mathematics.

Answer 2

It's more a method not a formula;
First of all, all par numbers aren't prime cause they can be devided by 2. Now how to tell if the number x is prime?
we start with d=3, if x/3 has no remaining, then x isn't prime, else d=d+2, so d=5... you continue till u reach d=x/2. if all x/d has remainings, then x is prime.
exemple:
x=17.
x/2=8

d=3
x/d=17/3 remaining

d=d+2=5
x/d=17/5 remaining

d=d+2=7
x/d=17/7 remaining
then 17 is a prime

another exemple:
x=21
x/2=10

d=3
x/d=21/3=7 no remaining
then 21 isn't prime.

This can get really annoying with big numbers such as tell if 12657 is prime. the best method here, before applying the one above, is to check if the number ends with 0 or 2 or 4 or 5 or 6 or 8, because it will not be prime. if the number ends with 1 or 3 or 7 or 9, check if the sum of all it's digit is equal to 3 or 6 or 9, for exemple the number 111 isn't prim cause 1+1+1=3. So the number 12657 is a real pain in the *** cause it doesn't satisfy any of the previous conditions so it should be worked with the first "hours taking" method. you would rather let the pc do it.

Answer 3

1. No. You have to check a number that looks like a prime for whether it has any factors. LOL.

2. If by "next prime number" you mean "the next HUGE prime number" then there's a formula that generates the next one to test. The huge prime numbers you hear about in the news are all Mersenne-format prime numbers, for which

potential Mersenne prime = 2^n - 1
where n is already known to be a prime.

Answer 4

a prime number factors are one and itself

If a number factors other than one and itself

Example

20 / 2

20 / 4

20 / 5

20 / 10

4, 4 5, and 10 can easily be devided into 20 Plus a and itself.

This number is called composit

The formula for a prime number . Check if the number is divisiable by one and itself.

- - - - - - -s-

Answer 5

It is knowm that there is no polynomial formula, however here is a formula for the nth prime.

Let p / q mean integer division (ignoring remainder).

Let floor( x ) = largest integer ≤ x .

Let π(n) = 1 + Σ [ j=2 to n ] ( (j-1)!+1 ) / j - (j-1)! / j .

Then nth prime =

1 + Σ [ m=1 to 2^n ] floor( ( n / ( 1 + π(m) ) ) ^ (1/n) )

Answer 6

no

Answer 7

i don't know now.