How to generate series in php with number gets multipled by 6 after every 2 numbers -

i thinking of algorithm can generate sequence where, 1000 numbers, every 3rd number multiplied 6. sample output this:

1 2 6 4 5 12 7 8 18 10 11 24 13 14 30 16 17 36 19 20 

something like:

function getnumber($i) {     if ($i % 3 == 0) {         return $i * 2;     } else {         return $i;     } }  ($i = 1; $i <= 1000; $i++) {     echo getnumber($i) . "\n"; } 

or, inline:

for ($i = 1; $i <= 1000; $i++) {     echo ($i % 3 ? $i : $i * 2) . "\n"; }