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#26 2013-01-22 09:06:38

Primenumbers
Member
Registered: 2013-01-22
Posts: 37

Re: Prime Numbers!!

For prime numbers (p), under 3 squared; p = 2a + 1 (where a = any whole number)
For prime numbers (r), under 5 squared; r = 3p +/- 2 or 4
For prime numbers (i), under 7 squared; i = 5r +/- 6 or 12 or 18 or 24
For prime numbers (m), under 11 squared; m = 7i +/- 30 or 60 or 90 or 120 or 150 or 180
For prime numbers (e), under 13 squared; e = 11m +/- 210 or 420 or 630 or 840 or 1050 or 1260 or 1470 or 1680 or 1890 or 2100

(A no. divisible by a, but not divisible by a group b +/- A no. divisible by group b, but not a = A no. not divisible by a or b.)

* Some rules give 1 but this is not prime.

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#27 2013-01-22 10:54:12

anonimnystefy
Real Member
From: The Foundation
Registered: 2011-05-23
Posts: 15,544

Re: Prime Numbers!!

Hi Primenumbers

Welcome to the forum! smile


“Here lies the reader who will never open this book. He is forever dead.

“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment

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#28 2013-01-22 13:09:17

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 87,258

Re: Prime Numbers!!

Hi Primenumbers;

Welcome to the forum!


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

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#29 2013-01-25 12:02:14

n872yt3r
Member
Registered: 2013-01-21
Posts: 392

Re: Prime Numbers!!

Prime numbers are numbers that have no other factors then one and itself. One is not a prime number... 1x1=1 and 1/1=1.
x = prime
y = anything other than 1 and x
z = composite
a = decimal
x/1=x. x/x=1. x/y=a.
z/1=z. z/z=1. z/y=y.
For something else on prime numbers... go to my Sieve of Eratosthenes post.


- n872yt3r
Math Is Fun Rocks! smile
By the power of the exponent, I square and cube you! cool

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#30 2014-06-25 08:33:21

cmowla
Member
Registered: 2012-06-14
Posts: 57

Re: Prime Numbers!!

kerr wrote:

http://en.wikipedia.org/wiki/Largest_known_prime_number
How is 17,425,170 a prime number? It is divisible by 2.
Thanks

It clearly says in plain English that this number is the number of digits of the largest known prime number.  You're welcome?

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#31 2014-06-25 11:01:24

bobbym
Administrator
From: Bumpkinland
Registered: 2009-04-12
Posts: 87,258

Re: Prime Numbers!!

Hi kerr;

is the prime number.


In mathematics, you don't understand things. You just get used to them.
Of course that result can be rigorously obtained, but who cares?
Combinatorics is Algebra and Algebra is Combinatorics.

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#32 2014-06-27 09:39:51

Primenumbers
Member
Registered: 2013-01-22
Posts: 37

Re: Prime Numbers!!

2+/-1..
6+/-1 5..
30+/- 1 7..
210 +/- 1 11..
2310 +/- 1 13..

equals primes......to a certain point above highest prime squared. e.g.>9,25,49,121 or 169 accordingly. And so on but the numbers get very big but you can do this up to infinity.

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#33 2014-08-16 02:50:25

Primenumbers
Member
Registered: 2013-01-22
Posts: 37

Re: Prime Numbers!!

The primes there are in a certain range can be estimated because there are;
1 No. not factorable by 2 in (2)
There are 2 No.'s not factorable by 2 or 3 in (6)
There are 8 No.'s not factorable by 2 or 3 or 5 in (30)
There are 48 No.'s not factorable by 2 or 3 or 5 or 7 or in (210)
times 48 by (prime -1) to get the next number of no.'s. i.e. =480 no.'s in (2310) not factorable by 2,3,5,7, or 11.....and so on.

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