Was just now solving it and came to see if others had the same issue. Yep, you are right.

    function generateRandomNumbers(c, n) {
      let randomNumbers = new Array(c);
      for (let i = 0; i < randomNumbers.length; i++) {
        let randomNumber = Math.floor(Math.random() * (n + 1));
        randomNumbers[i] = randomNumber;
      }
      return randomNumbers;
    }
    function run(w, wS, m, r) {
        function round(r) {
            while(wS.size < m) {
                const next = w.next()
                if (next.done) return true;
                wS.add(next.value)
                prune(next.value, r)
            }
            return false
        }
        function prune(v,r) {
            for (let i = 0; i < r; i++) {
                const flip = new Boolean(Math.round(Math.random()))
                if (flip == false) {
                    wS.delete(v)
                }
            }
        }
        function purge(wS) {
            const copy = new Set(wS)
            copy.forEach(ith=>{
                const flip = new Boolean(Math.round(Math.random()))
                if (flip == false) {
                    wS.delete(ith)
                }
            })
        }
        const done = round(r);
        if (!done) {
            purge(wS)
            return run(w, wS, r+1,m)
        }
        console.log(`Round ${r} done. ${wS.size} Estimate: ${wS.size / (1/Math.pow(2,r))}`)
    }
    const memory = 1000
    const words = generateRandomNumbers(3000000,15000)
    const w = words[Symbol.iterator]() // create an iterator
    const wS = new Set();
    run(w,wS, memory,0);