PHP - Ayuda con secuencia fibonacci PHP

<?php

$n1=0;

$n2=1;

for ($i=0; $i<5;$i++){

$suma=$n1+$n2;

$n1=$n2;

$n2=$suma;

echo $suma."</br>";

$aux[$i] = $suma;

}

?>

<?php

$n1=0;

$n2=1;

$total=0;

for ($i=0; $i<5;$i++){

	$suma=$n1+$n2;

	$total+=$suma;

	$n1=$n2;

	$n2=$suma;

	echo $suma."</br>";

	$aux[$i] = $suma;

}

echo "Total: ".$total;

?>

$aux[$i] = $suma;

<?php

$fibonacci = array();

$fibonacci[0] = 0;

$fibonacci[1] = 1;

for ($i = 2; $i < 50; $i++) {

  $fibonacci[$i] = $fibonacci[$i - 1] + $fibonacci[$i - 2];

}

print array_sum($fibonacci);

?>