C :

#include<stdio.h>
int suShu(int x){
		int i;
	if(x>1){
		int c=0;
		for(i=2;i<=x/2;i++){
			if(x%i==0){
				c++;
				break;
			}
		}
		if(c==0){
			return 1;
		}else{
			return 0;
		}
	}else{
		return 0;
	}
}
int main()
{
	int a,b;
	for(a=2;a<=100;a++){
		for(b=a+1;b<=100;b++){
			if(suShu(a)&&suShu(b)&&suShu((a+b)/2)&&(a+b)%2==0){
				printf("%d %d %d\n",a,(a+b)/2,b);
			}
		}
			
	}
	return 0;
}

Python :

import math
def suShu(n):
        f = True
        for i in range (2 , int(math.sqrt(n))+1):
                if n % i == 0:
                        f = False
                        break;
        return f and n != 1

for i in range (1, 100):
        for e in range (i + 1, 100):
                if suShu(i) and suShu(e) and suShu((i+e)//2) and (i + e) % 2 == 0:
                        print(i, (i+e)//2, e)