Hello all,

Straight to the question -

If $n = 3,

and input is -

Array
(
    [04] => 3
    [07] => 4
    [01] => 5
    [06] => 5
    [05] => 5
    [03] => 6
    [08] => 6
    [02] => 7
    [09] => 8
    [12] => 9
    [10] => 10
    [15] => 10
    [19] => 11
    [20] => 11
    [13] => 12
    [21] => 12
    [16] => 13
    [14] => 14
    [22] => 14
    [23] => 15
    [11] => 15
    [00] => 15
    [17] => 17
    [18] => 17
)

Output should be -

Array
(   [14] => 14
    [22] => 14
    [23] => 15
    [11] => 15
    [00] => 15
    [17] => 17
    [18] => 17
)

Thank you, all, for help.