Akm[k_,m_]:=Piecewise[{{(Ea1u + Ea2u1 + Ea2u2 + 2*Eeu1 + 2*Eeu2)/7, k == 0 && m == 0}, {(-5*(5*Ea1u + 5*Ea2u1 - 4*Ea2u2 - 6*Eeu1))/28, k == 2 && m == 0}, {((-3/2 + (3*I)/2)*(3*Ma2u + 2*Sqrt[2]*Meu))/Sqrt[7], k == 4 && m == -3}, {(3*(3*Ea1u + 3*Ea2u1 + 2*(3*Ea2u2 + Eeu1 - 7*Eeu2)))/14, k == 4 && m == 0}, {((3/2 + (3*I)/2)*(3*Ma2u + 2*Sqrt[2]*Meu))/Sqrt[7], k == 4 && m == 3}, {((13*I)/20)*Sqrt[33/7]*(Ea1u - Ea2u1), k == 6 && m == -6}, {(13/10 - (13*I)/10)*Sqrt[3/7]*(Ma2u - 3*Sqrt[2]*Meu), k == 6 && m == -3}, {(-13*(Ea1u + Ea2u1 - 20*Ea2u2 + 30*Eeu1 - 12*Eeu2))/140, k == 6 && m == 0}, {(-13/10 - (13*I)/10)*Sqrt[3/7]*(Ma2u - 3*Sqrt[2]*Meu), k == 6 && m == 3}, {((-13*I)/20)*Sqrt[33/7]*(Ea1u - Ea2u1), k == 6 && m == 6}}, 0]