<?php

function freqCount($array, $element)
{
    $result = [[0, 0]];
    foreach ($array as $arrayElement) {
        if (is_numeric($arrayElement) && $arrayElement == $element) {
            foreach ($result as $index => $level) {
                if ($level[0] == 0) {
                    $result[$index][1]++;
                }
            }
        }
        if (is_array($arrayElement)) {
            $internalResult = freqCount($arrayElement, $element);
            foreach ($internalResult as $internalLevel) {
                $found = false;
                foreach ($result as $index => $level) {
                    if ($level[0] == 1 + $internalLevel[0]) {
                        $result[$index][1] += $internalLevel[1];
                        $found = true;
                        break;
                    }
                }
                if (!$found) {
                    $result [] = [$internalLevel[0] + 1, $internalLevel[1]];
                }
            }
        }
    }
    return $result;
}

$array = [1, 4, 4, [1, 1, [1, 2, 1, 1]]];
print_r (freqCount($array, 1));