This results in a set of equations for which the solutions are ⟨ j ‖ K ( 1 ) ‖ j ⟩ = i j 1 j 0 j ( j + 1 ) , ⟨ j ‖ K ( 1 ) ‖ j − − 1 ⟩ = − − B j ξ ξ j j ( 2 j − − 1 ) , ⟨ j − − 1 ‖ K ( 1 ) ‖ j ⟩ = B j ξ ξ j − − 1 j ( 2 j + 1 ) , where B j = ( j 2 − − j 0 2 ) ( j 2 − − j 1 2 ) j 2 ( 4 j 2 − − 1 ) , j 0 = 0 , 1 2 , 1 , … … and j 1 , ξ ξ j ∈ ∈ C .