If its not frontpage

Could somebody please tell me how to write

<?php if (in_category( array(10,11,12,13,14,15,18,19,20) )) { ?> 

and if its not frontpage ?

You have the WordPress function is_front_page() that you need to invert with “!” .

if(!is_front_page() && in_category( array(10,11,12,13,14,15,18,19,20) ))