C :

#include<stdio.h> 
int main(){
	int n,i,j,k;
	scanf("%d",&n);
	int a[n][n];
	for(i=0;i<n;i++){
		k=1;
		for(j=0;j<n-i-1;j++){
			a[i][j]=k;
		}
		for(j=n-i-1;j<n;j++){
			a[i][j]=k++;
		}
	}
		for(i=0;i<n;i++){
			for(j=0;j<n;j++){
				if(i+j>=n-1){
					printf("%5d",a[i][j]);
				}else{
					printf("%5s","");
				}
			}
		printf("\n");
	}
	return 0;
}

C++ :

#include <bits/stdc++.h>
using namespace std;

int main(){
	int a[100][100] = {0};
	int i,j,n;
	cin>>n;
	
	for (i = 0;i < n;i++){
		for (j = 0;j <= i;j++){
			a[i][j + n - i - 1] = j + 1;
		}
	}
	
	for (i = 0;i < n;i++){
		for (j = 0;j < n;j++){
			if (a[i][j] == 0){
				cout<<setw(5)<<" ";
			}else{
				cout<<setw(5)<<a[i][j];
			}
		}
		cout<<endl;
	}
}

Python :

n = int(input())
a = [[0 for j in range(n)] for i in range(n)]

for i in range(n):
    a[i][n-i-1] = 1
    for j in range(n-i, n):
        a[i][j] = a[i][j - 1] + 1

for i in range(n):
    for j in range(n):
        if a[i][j]==0:
            print('%5s' % '', end='')
        else:
            print('%5d' % a[i][j], end='')
    print()