for (int64_t i = a - 1; i < b; ++i) {
        if (i == a - 1) {
            for (int j = 0; j < n + 1; ++j){
                printf(" ");
            }
            for (int64_t j = a; j < b; ++j) {
                printf("%*lld", n, j);
                printf(" ");
            }
        } else {
            printf("%*lld", n, i);
            printf(" ");
            for (int64_t j = a; j < b; ++j) {
                printf("%*lld", n, i * j);
                printf(" ");
            }
        }
        printf("\n");
    }