попробуй так))
$arFilter = Array(
"IBLOCK_ID"=>ид_инфоблока_каталога,
"ID"=>[COLOR=#0000FF]range([/COLOR][COLOR=#0000FF]71450, 72000)[/COLOR],
"ACTIVE"=>"Y",
);
$res = CIBlockElement::GetList(Array("SORT"=>"ASC"), $arFilter, false, false, array('ID'));
while($ar_fields = $res->GetNext())
echo $ar_fields["ID"] . "<br>";