#include <stdio.h>
#define MAX 20

int main(void) {
  int i, j, sum;

  for(i = 1; i <= MAX; i++){
    sum = 0;

    for(j = 1; j <= i; j++){
      sum += j;
    }

    printf("Sum of 1 to %d: %d\n", i, sum);
  }
   
  
  return 0;
}