/*
calculates two strings to a new string ... calc("1234", "1234") -> "2468"
*/
function calc($a, $b){
        $result = "";//final result
        $len_1 = strlen($a);
        $len_2 = strlen($b);
        if($len_1 > $len_2){
                $up = $len_1;
        }else{
                $up = $len_2;
        }
        $a =  strrev ( $a );
        $b =  strrev ( $b );

        $arr1 = str_split($a);
        $arr2 = str_split($b);

        for($i = 0;$i < ($up+1);$i++){
                $numb = $jj + $arr1[$i] + $arr2[$i];
                if($numb >= 10){
                        $jj = 1;
                        $numb = ($numb % 10);
                }else{
                        $jj = 0;
                }
                $result = $numb."".$result;
        }
        return ltrim($result, "0");
}

$fibo_1 = "1";
$fibo_2 = "1";

for($i = 1;$i <= 201;$i++){
        $new = calc($fibo_1, $fibo_2);
        echo "".$new."";
        if($i % 2 == 0){
                $fibo_1 = $new;
        }else{
                $fibo_2 = $new;
        }
}