test.php

<?php
require_once 'app/Mage.php';


/**
 * Error reporting
 */
error_reporting(E_ALL | E_STRICT);
ini_set('display_errors', 1);


$app = Mage::app();
printf("Current ID: %d<br/>",$app->getStore()->getRootCategoryId());
$collection = Mage::getResourceModel('catalog/product_collection');
$collection->addStoreFilter();

 $i=0;

for($i=1;$i<20;$i++){
    $category = Mage::getModel('catalog/category')->load($i);
    if($category->getLevel() > 1) continue;
    $collection = Mage::getResourceModel('catalog/product_collection')
        ->setStoreId($app->getStore()->getId())
        ->addCategoryFilter($category)->addAttributeToFilter('status', array('eq' => 1));
    Mage::getSingleton('catalog/product_visibility')->addVisibleInCatalogFilterToCollection($collection);

    printf("%s (%d)=>%s<br/>",$category->getName(),$i,$collection->count());
}



die();