A few Gegenbauer polynomials for λ = -3/8 -0.1048 -0.03626 0.03228 0.1008 0.1694 0.2379 0.3065 0.375 -0.8 -0.6 -0.4 -0.2 5.551e-17 0.2 0.4 0.6 0.8 1