Array
(
    [0] => 20110911
    [1] => 20110913
    [2] => Array
        (
            [0] => 20110915
            [1] => 20110918
        )

    [3] => 20110920
    [4] => 20110922
    [5] => 20110924
    [6] => Array
        (
            [0] => 20110926
            [1] => 20110927
        )

    [7] => 20110929
)

show code


<?php echo "<pre>";

print_r( json_decode('[20110911, 20110913, [20110915, 20110918], 20110920, 20110922, 20110924, [20110926, 20110927], 20110929]')); echo "</pre>";