C :

#include<stdio.h>
int main()
{
    int i;
    int m,n;
    scanf("%d%d",&m,&n);
    for(i=m;i<=n;i++)
    {
        if(i<1000)
        {
            if((i/100+i%10)==2*(i/10%10))
        {
            printf("%d\n",i);
        }
        }
            if(i>=1000)
            {
                if((i/1000-i/100%10)==(i/100%10-i/10%10)&&(i/100%10-i/10%10)==(i/10%10-i%10))
                {
                    printf("%d\n",i);
                }
            }
        
    }
    return 0;
}

C++ :

#include <bits/stdc++.h>
using namespace std;
int main(){
	int i,m,n,g,s,b,q;
	cin>>m>>n;
	for(i = m;i <= n;i++){
		q = i / 1000;
		b = i / 100 % 10;
		s = i / 10 % 10;
		g = i % 10;
		
		if(i >= 1000 && q - b == b - s && b - s == s - g){
			cout<<i<<endl;
		}else if(i >= 100 && i <= 999 && b - s == s - g){
			cout<<i<<endl;
		}
	}
}

Python :

m,n = map(int,input().split());
for i in range (m, n+1):
    a = i // 1000
    b = i // 100 % 10
    c = i // 10 % 10
    d = i % 10
    if a == 0 and b - c == c -d:
        print(i)
    elif a - b == b -c and b -c == c - d:
        print(i)