List of recent champions for factoring Cunningham numbers: Quadratic sieve method: 4682 C135 2,1606L Dodson, A.K. Lenstra, Leyland, Muffett, Wagstaff 4564 C124 2,895- Jens Franke Special number field sieve by size of number factored: 4703 C227 2,751- CWI/Dodson/Franke/AKL/Leyland 4530 C227 2,773+ The Cabal 4677 C219 2,727- Dodson/AKL/CWI Special number field sieve by SNFS difficulty: 4703 C227 2,751- CWI/Dodson/Franke/AKL/Leyland 4530 C227 2,773+ The Cabal 4677 C219 2,727- Dodson/AKL/CWI General number field sieve by size of number factored: 4701 C158 2,953+ F. Bahr + J. Franke + T. Kleinjung 4559 C142 2,779- B. Dodson + CWI + A. K. Lenstra + Edick + P. Leyland 4447 C141 10,212+ A. K. Lenstra + B. Dodson + F. Morain + CWI Largest penultimate prime factor (ultimate factor shown also): 4677 p98*p128 2,727- Dodson/AKL/CWI 4342 p93*p118 10,211- The Cabal First five holes in each table on May 17, 2002 2,673- c151 2,713- c171 2,719- c208 2,731- c183 2,739- c168 2,653+ c154 2,659+ c188 2,661+ c148 2,667+ c161 2,671+ c165 2,1238L c160 2,1238M c145 2,1262L c177 2,1262M c178 2,1294L c187 2,716+ c163 2,736+ c172 2,760+ c153 2,764+ c220 2,772+ c215 3,397- c178 3,431- c198 3,437- c151 3,443- c187 3,449- c175 3,397+ c162 3,404+ c141 3,409+ c161 3,412+ c195 3,419+ c173 5,307- c187 5,311- c173 5,313- c210 5,317- c194 5,319- c182 5,289+ c156 5,298+ c189 5,302+ c187 5,304+ c172 5,307+ c159 6,257- c173 6,263- c196 6,277- c139 6,281- c162 6,283- c173 6,251+ c179 6,257+ c200 6,263+ c186 6,268+ c138 6,269+ c135 7,233- c155 7,253- c177 7,257- c192 7,259- c175 7,263- c161 7,232+ c171 7,233+ c150 7,239+ c176 7,253+ c164 7,254+ c178 10,223- c211 10,227- c212 10,233- c162 10,239- c228 10,241- c229 10,223+ c201 10,226+ c197 10,229+ c164 10,232+ c205 10,233+ c207 11,199- c173 11,217- c171 11,221- c135 11,227- c195 11,229- c217 11,197+ c161 11,206+ c213 11,208+ c185 11,212+ c201 11,218+ c192 12,179- c190 12,193- c199 12,197- c212 12,199- c146 12,215- c182 12,178+ c145 12,202+ c216 12,206+ c192 12,208+ c202 12,209+ c185