Javascript Random Number Generator

I'm trying to get 8 random numbers between 1-80 and put them into specified divs.

var numbers = []
var luckyNumber;
var x = 1;

while (x < 8) {
  luckyNumber = Math.floor(Math.random() * 80 + 1);
  if (numbers.indexOf(luckyNumber) == -1) {
    for (var i = 1; i < 9; i++) {
      document.getElementById('k' + i).innerHTML = numbers[i]
    }
    numbers.push(luckyNumber);
    x++;
  }
}

document.write(numbers);

<div id="k1">K1</div>
<div id="k2">K2</div>
<div id="k3">K3</div>
<div id="k4">K4</div>
<div id="k5">K5</div>
<div id="k6">K6</div>
<div id="k7">K7</div>
<div id="k8">K8</div>

The last 2 numbers are shown undefined in HTML result. But if you check the numbers with document.write you can see the last two numbers. How can I solve this problem?