0 10 20 30 40 50 60 r$_{sc }$ [fm] -2.1 -2.08 -2.06 -2.04 [tan $_{δ}$c,k ] 2nd n=1 n=2 n=3 n=4 n=5 n=6 tan c FIG. 6: (Color on line) The three-nucleon second order estimate [tan δ$_{c,k}$ ] 2 nd as a function of r$_{sc}$ for different values of n , at E = 0 . 2 MeV. As a reference the exact value for tan δ$_{c}$ is given as a straight line. 33