Where does “हख़ामन” come from?

हख़ामन (Hindi) comes from Persian هخامنش, from Old Persian 𐏃𐎧𐎠𐎶𐎴𐎡𐏁, from Proto-Indo-European sekʷ- — to follow; to see; to say.

हख़ामन (Hindi): Achaemenes (the founder of the Achaemenid dynasty)