1 (k^2*(3 - 2*Sqrt[1 + k^2/(c - I*k0)^2])*(c - I*k0)^2 - 2*(-1 + Sqrt[1 + k^2/(c - I*k0)^2])*(c - I*k0)^4 + 2*k^2*(-3 + 2*Sqrt[1 + k^2/(2*c - I*k0)^2])*(2*c - I*k0)^2 + 4*(-1 + Sqrt[1 + k^2/(2*c - I*k0)^2])*(2*c - I*k0)^4 + k^2*(3 - 2*Sqrt[1 + k^2/(3*c - I*k0)^2])*(3*c - I*k0)^2 - 2*(-1 + Sqrt[1 + k^2/(3*c - I*k0)^2])*(3*c - I*k0)^4)/(6*k^3*k0^3)
2 SeriesData[k, Infinity, {c^2/k0^3, (-3*(2*c^3 - I*c^2*k0))/k0^3, (2*(25*c^4 - (24*I)*c^3*k0 - 6*c^2*k0^2))/(3*k0^3), (-5*(18*c^5 - (25*I)*c^4*k0 - 12*c^3*k0^2 + (2*I)*c^2*k0^3))/(4*k0^3), 0, ((c - I*k0)^7/8 - (2*c - I*k0)^7/4 + (3*c - I*k0)^7/8)/(6*k0^3), 0, ((-3*(c - I*k0)^9)/64 + (3*(2*c - I*k0)^9)/32 - (3*(3*c - I*k0)^9)/64)/(6*k0^3), 0, ((3*(c - I*k0)^11)/128 - (3*(2*c - I*k0)^11)/64 + (3*(3*c - I*k0)^11)/128)/(6*k0^3)}, 1, 11, 1]