I am trying to create a function which maps a recurring pattern of integers using an array.

As an example if I have a starting array of (0,1,3) and I know that I want to stop the pattern when I hit 15.

The pattern gets incremented by a fixed integer each time (lets say 4) so my final pattern should be..

0
1
3
4 (0 + 4)
5 (1 + 4)
7 (2 + 4)
8 (4 + 4)
9 (5 + 4)
11(7 + 4)
12(8 + 4)
13(9 + 4)
15(11+ 4)

Does anyone have any pointers on how this can be achieved?

My current implementation works but is stupidly inefficient which something like this...

$array = array(0,1,3);
$inc = 4;
$end = end($array);
$final = 15;

while($end < $final)
{
$tmp = array();
foreach($array AS $row)
{
$tmp = $row + $inc;
}
$array = merge($tmp, $array);
$end = end($array);
}