C++ :

#include <bits/stdc++.h>
using namespace std;
int main(){
	int g,s,b,q,w,i,s1,s2,s3,k,f = 0;
	cin>>k;
	for(i = 10000;i <= 30000;i++){
		w = i / 10000;
		q = i / 1000 % 10;
		b = i / 100 % 10;
		s = i / 10 % 10;
		g = i % 10;
		
		s1 = w * 100 + q * 10 + b;
		s2 = q * 100 + b * 10 + s;
		s3 = b * 100 + s * 10 + g;
		
		if(s1 % k == 0 && s2 % k == 0 && s3 % k == 0){
			cout<<i<<endl;
			f = 1;
		}
	}
	
	if(f == 0){
		cout<<"No"<<endl;
	}
}

Python :

k=int(input())
s=0
for i in range(10000,30001):
    a=i//100
    b=i//10%1000
    c=i%1000
    if a%k==0 and b%k==0 and c%k==0:
        s+=1
        print(i)
if s==0:         
    print('No')