1 ((-4*(-1 + Sqrt[1 + k^2/(c - I*k0)^2])*(c - I*k0))/k + (6*(-1 + Sqrt[1 + k^2/(2*c - I*k0)^2])*(2*c - I*k0))/k - (4*(-1 + Sqrt[1 + k^2/(3*c - I*k0)^2])*(3*c - I*k0))/k + ((-1 + Sqrt[1 + k^2/(4*c - I*k0)^2])*(4*c - I*k0))/k + (Sqrt[Pi]*(Piecewise[{{0, k^2/k0^2 <= 1}}, (2*Sqrt[k^2 - k0^2])/(k*Sqrt[Pi])] + I*Piecewise[{{(2*k0)/(k*Sqrt[Pi]), k0^2/k^2 < 1}, {(2*(k0 - Sqrt[-k^2 + k0^2]))/(k*Sqrt[Pi]), k0^2/k^2 > 1}}, 0]))/2)/k0^2
2 Piecewise[{{SeriesData[k, Infinity, {(-3*c^4)/k0^2, 0, (-45*c^4)/2 + (195*c^6)/(2*k0^2) - ((90*I)*c^5)/k0, 0, (6825*c^6)/4 - (25515*c^8)/(16*k0^2) + ((2625*I)*c^7)/k0 - (525*I)*c^5*k0 - (525*c^4*k0^2)/8, 0, (105*(6821*c^10 - (15540*I)*c^9*k0 - 15309*c^8*k0^2 + (8400*I)*c^7*k0^3 + 2730*c^6*k0^4 - (504*I)*c^5*k0^5 - 42*c^4*k0^6))/(32*k0^2)}, 4, 11, 1], (k0 <= 0 && k^2/k0^2 > 1) || k0 > 0}}, SeriesData[k, Infinity, {-k0^(-2), 0, 1/2, 0, ((c*(c - I*k0)^3)/2 - (3*c*(2*c - I*k0)^3)/2 + (3*c*(3*c - I*k0)^3)/2 - (c*(4*c - I*k0)^3)/2 - I/2*(c - I*k0)^3*k0 + (3*I)/4*(2*c - I*k0)^3*k0 - I/2*(3*c - I*k0)^3*k0 + I/8*(4*c - I*k0)^3*k0)/k0^2, 0, (-(c*(c - I*k0)^5)/4 + (3*c*(2*c - I*k0)^5)/4 - (3*c*(3*c - I*k0)^5)/4 + (c*(4*c - I*k0)^5)/4 + I/4*(c - I*k0)^5*k0 - (3*I)/8*(2*c - I*k0)^5*k0 + I/4*(3*c - I*k0)^5*k0 - I/16*(4*c - I*k0)^5*k0)/k0^2, 0, ((5*c*(c - I*k0)^7)/32 - (15*c*(2*c - I*k0)^7)/32 + (15*c*(3*c - I*k0)^7)/32 - (5*c*(4*c - I*k0)^7)/32 - (5*I)/32*(c - I*k0)^7*k0 + (15*I)/64*(2*c - I*k0)^7*k0 - (5*I)/32*(3*c - I*k0)^7*k0 + (5*I)/128*(4*c - I*k0)^7*k0)/k0^2, 0, ((-7*c*(c - I*k0)^9)/64 + (21*c*(2*c - I*k0)^9)/64 - (21*c*(3*c - I*k0)^9)/64 + (7*c*(4*c - I*k0)^9)/64 + (7*I)/64*(c - I*k0)^9*k0 - (21*I)/128*(2*c - I*k0)^9*k0 + (7*I)/64*(3*c - I*k0)^9*k0 - (7*I)/256*(4*c - I*k0)^9*k0)/k0^2}, 0, 11, 1]]