Showing posts with label mathematics problem. Show all posts
Showing posts with label mathematics problem. Show all posts

Friday, April 29, 2011

WAP to find Nth Twin prime Efficiently-UnSolved Problem In Mathematics In Prime Number Theory

You will have to take an integer n as input. and output should be the nth twin prime pair

A twin prime is a prime number that differs from another prime number by two. Except for the pair (2, 3), this is the smallest possible difference between two primes. Some examples of twin prime pairs are (3, 5), (5, 7), (11, 13), (17, 19), (29, 31) and (41, 43). Sometimes the term twin prime is used for a pair of twin primes; an alternative name for this is prime twin.


public class TwinPrime {

public static void main(String a[])
{
boolean flag=false; int i,n=10024;
boolean k=false;
for(i=3;n>0;i+=2)
{
k=isPRIME(i)==true && isPRIME(i+2)==true;
if(k)
n--;
//System.out.println( "" + i + "" + (i+2));
}
System.out.println("Twins Prime are:" + (i-2) + ":" + i);
}

static boolean isPRIME(int x)
{
int i=0;
if(x <= 1)
return false;
int s = (int)Math.sqrt(x);
for(i = 2; i <= s; i++)
if(x%i == 0)
{
//System.out.println("" + x + "is prime" );
return false;
}
return true;
}


}

List : http://primes.utm.edu/lists/small/100ktwins.txt
Run Here http://ideone.com/TeJKSv