Revision 6828b8f8-cbc0-4fed-b66f-e19bff72165c - Code Golf Stack Exchange

# PHP, 69+1 bytes

<!-- language: lang-php -->

 for($n=$argn;$n>0;$n-=20)if($n%3<1)for($k=$n;$k>0;$k-=9)$k%6||die(1);

exits with `1` for a Chicken McNugget Number, `0` else.

Run as pipe with `-n` or [try it online](http://sandbox.onlinephpfunctions.com/code/62476ac2ca9c1cef991499ce4c7cfd847e062c40).