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