I've the following arrays:
Array
(
    [13699] => Array
        (
            [0] => 13699
        )
)
Array
(
    [13699] => Array
        (
            [0] => 13699
            [1] => 13699
            [2] => 13699
            [3] => 13699
            [4] => 13699
        )
)
Both arrays have the same key(13699), how do i merge them to get the value from the second array added to the value of the first array? like this:
Array
    (
        [13699] => Array
            (
                [0] => 13699
                [1] => 13699
                [2] => 13699
                [3] => 13699
                [4] => 13699
                [5] => 13699
            )
    
    )
I've tried for hours with array_merge, and array_merge_recursive but without any luck to achieve what i want.
Thanks.
