C++ :

#include<iostream>
#include<iomanip>
using namespace std;
//int ;
int main()
{
	int n,a[21][21];
	cin>>n;
	for (int i=1,k=1; i<=n; i++)
		for (int j=i,x=1; x<=i; j--) a[x++][j]=k++;
	for (int i=1; i<=n; i++)
	{
		for (int j=1; j<=n-i+1; j++) cout<<setw(4)<<a[i][j];
		cout<<endl;
	}
	return 0;
}