x(-1)= 1 x(0) = 1 x(i) = x(i-1) + i; i=0,1,2...,n-1

y(i,0) = x(i) y(i,j) = y(i,j-1) + i + j + 1; j=1,...,n-i-1

#include <stdio.h>
int main(){
    int n;
    scanf("%d",&n);
    
    int numy;
    int numx = 1;
    for(int i=0; i<n; i++){
        numx = numx + i;
        printf("%d ", numx);
        numy = numx;
        for(int j=1; j<(n - i); j++){
            numy = numy + i + j + 1;
            printf("%d ", numy);
        }
        printf("\n");
    }
    
    return 0;
}