The versatile code injects for instance adsense ad codes several times into the posts of an index or archive page, starting with a pre-set post, and then repeated in regular intervals (up to a set limit of ads per page).
For example, in a child theme of Twenty Fourteen, this code would be added into content.php at a suitable location:
<?php
//set the variables//
$nth = 3; //1,2,3,,4...; repeated every n-th post
$snr = 1; //1,2,3...; pre-set start with post nr
$limit = 3; //adsene TOS limit of ads per web page
$lsnr = $snr - 1; // correct for loop counter start at zero
if( $wp_query->current_post >= $lsnr && ( $wp_query->current_post - $lsnr )%$nth == 0 && (int)(( $wp_query->current_post - $lsnr ) / $nth ) < $limit ) { ?>
ADSENSE CODE
<?php } ?>
The example values would start the add in the first post, and repeated every three posts for a maximum of 3 ads.
