function count_unique_3(n, k, j = 0) {
    let rows = [];

    subset = [];

    function subsets(n, k, j = 0) {
        if (subset.length == k) {
            rows.push(subset.slice(0));
        } else {
            for (let i = j+1; i <= n-k+1+subset.length; ++i) {
                subset.push(i);
                subsets(n,k,i);
                subset.pop();
            }
        }
    }

    subsets(n, k);

    return rows;
}