3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php $sum = 0; while($sum<=5050){ $sum += $sum+1; echo $sum."\n"; }
Output for 4.3.0 - 7.1.0
1 3 7 15 31 63 127 255 511 1023 2047 4095 8191