Help with mathmatical custom function

function factorial($number) {
        if ($number == 0) return 1;
        return $number * factorial($number - 1);
}

PHP:

On the internet I have found this function which states the factorial of a number.

I now want to make a function where basically there will be a user inputted number say x and a power y, but then i want to add x^y to x^y-1 ... x^y-y+1 where y-y+1 is one.

This could be used in non-repetitive combinations for example where for a 4 length combination with 10 possible values for each digit would be 10^4 + 10^3 + 10^2 + 10^1 = 10000 + 1000 + 100 + 10 = 11110

Thanks

 

<?php
function combination($number, $number2) {
        if ($number == 0) return;
        return pow($number2, $number) + combination($number - 1, $number2);
}
echo combination(4, 10);
?>

PHP:

Output: 11110

It should guide you to where you want to go. Rep is appreciated

Jay

 

function factorial($number,$number2) { if ($number == 0) return 1;
else
{
$sum=0;
for ($i=$number2;$i>=1;$i--)
{
$sum=pow($number,$i)+sum;
}
return $sum;
}

}