$ JS Shuffled Sequences

<!DOCTYPE html>
<html>
<head>
<title>Shuffled Sequences</title>
</head>
<body>
<div id="output"></div>
<script>
let n = 10;
let counter = 0;
let output = document.getElementById("output");
let integers = [];
for (let i = -n; i <= n; i++) {
    integers.push(i);
}

for (let i = 0; i <= 18; i++) {
    integers = integers.concat(integers);
}

let L = integers.length;

function shuffle() {
    let element = integers.splice((counter ** 5) % L, 1)[0];
    integers.push(element);
}

function printSequence() {
    shuffle();
    output.innerHTML += integers[L - 1] + " ";
    counter++;
    if (counter > L) {
        counter = 0;
    }
    setTimeout(printSequence, 1);
}
printSequence();
</script>
</body>
</html>