3v4l.org

run code in 300+ PHP versions simultaneously
<?php $n = array(1, 3); $k = 0; $x = 1; $z[] = $x; for ($i = 1; $i < 300; $i++) { $x += $n[$k]; $z[] = $x; if ($k == 0) $k = 1; else $k = 0; } echo implode(',', $z);

preferences:
36.55 ms | 402 KiB | 5 Q