Equation Icon  D2 ^n1 ≡ − 1n −3∕2[Δ (n+1∕2)]^n1 + 1n− 1∕2Δ (n− 1∕2^n1) (262 ) 2 c c 2 c c 1- −1 ≈ + 2n c [Δ^n1 ] (263 ) 1 = − -n −c1k2^n1. (264 ) 2