<?php

    #fibonacci formula
    function fibonacciTest($param){
        #Using Binet's Formula for efficiency
        return ((1 + (sqrt(5)))**$param - (1 - (sqrt(5)))**$param)/(2**$param * sqrt(5));
    }

    #list fibonacci numbers and sum only even numbers
    function eulerFib($param){
        #create an array
        $array = array();
        #start a loop
        for($i = 0; $i <= $param; $i++){
            #call a recursive function
            $results = fibonacciTest($i);
            #list fibonacci numbers
            echo "#" . $i . " = " . $results . "\n";
            #only push even numbers to array
                if($results % 2 === 0){
                    array_push($array, $results);
                }
        }
        #print results and answer
        print_r($array);
        Print "Total = " . array_sum($array) . "\n";
    }

    #call function
    eulerFib(33);   #for fibonacci values less than 4,000,000 the answer is 4,613,762

 ?>