Loading numbers into a PHP array - unexpected problems

I'm trying to define an array of numbers like this:

$days_pages = array(
'monday' => array(001, 002, 003, 004, 005, 006, 007, 008, 009, 010, 011, 012, 013, 014, 015, 016, 017, 018, 019, 020),
...
);

However, when I do:

print_r($days_pages);

it shows

Array
(
    [monday] => Array
        (
            [0] => 1
            [1] => 2
            [2] => 3
            [3] => 4
            [4] => 5
            [5] => 6
            [6] => 7
            [7] => 0   **************
            [8] => 0   **************
            [9] => 8
            [10] => 9
            [11] => 10
            [12] => 11
            [13] => 12
            [14] => 13
            [15] => 14
            [16] => 15
            [17] => 1    **************
            [18] => 1    **************
            [19] => 开发者_运维问答16
            [20] => 17

I dont understand why this would be happening - what am I doing wrong?

---

If an invalid digit is given in an octal integer (i.e. 8 or 9), the rest of the number is ignored

like

<?php
var_dump(01090); // 010 octal = 8 decimal
?>

so

008, 009

its not valid and be 0

look also in previous post on octal numbers (a few minutes ago)

related to php arithmetic

---

in php integer varaiables take octal that hwy you face this problem.

Show this link first.you can understand.

http://www.ascii.cl/conversion.htm