coopster - 10:56 pm on Jan 20, 2013 (gmt 0)

Modulus may not be your best option in this case because what if you needed a class on the second div? 2 and 4 are both going to be equally divisible on certain integers in your set. I think you may be better served using a counter:

<pre> 
<?php 
// set your alpha/omega here: 
$alpha = 1; 
$omega = 4; 
$reset = 5; // how many total divs before next set? 
$count = 0; // initialize our counter 
for ($i = 1; $i <= 28; $i++) { 
  if (++$count == $reset) { // increase and compare 
    $count = 1; // reset if necessary 
  } 
  if ($count == $alpha) { 
    print '&#60;div class="alpha"&#62; '; 
  } else if ($count == $omega) { 
    print '&#60;div class="omega"&#62;'."\n"; 
  } else { 
    print '&#60;div&#62; '; 
  } 
} 
exit; 
?> 
<pre> 

<div class="alpha"> <div> <div> <div class="omega"> 
<div class="alpha"> <div> <div> <div class="omega"> 
<div class="alpha"> <div> <div> <div class="omega"> 
<div class="alpha"> <div> <div> <div class="omega"> 
<div class="alpha"> <div> <div> <div class="omega"> 
<div class="alpha"> <div> <div> <div class="omega"> 
<div class="alpha"> <div> <div> <div class="omega">