f = 0 * z + 0.538661262290775 *z^2/2 + 0.734852018312207 *z^3/3 + 0.836173130992059 *z^4/4 + 0.895702100822282 *z^5/5 + 0.933348094773875 *z^6/6 + 0.957889535263102 *z^7/7 + 0.974172350315006 *z^8/8 + 0.984170385706758 *z^9/9 + 0.99099470856923 *z^10/10 + 0.995340577512101 *z^11/11 + 0.998038292064791 *z^12/12 + 0.999662655985021 *z^13/13 + 1.00062417528038 *z^14/14 + 1.00120688321173 *z^15/15 + 1.00161264841716 *z^16/16 + 1.00049427058314 *z^17/17 + 1.00042659683495 *z^18/18 + 1.00036097870163 *z^19/19 + 1.00032306352476 *z^20/20; d = Normal[Series[Exp[-f],{z,0,20}]]; r = z/.{ToRules[Roots[d==0,z]]}; (* InputForm[r] shows all digits *) rr = Table[{Re[r[[i]]], Im[r[[i]]]}, {i, 1, 20}]; ListPlot[rr];