List of recent champions for factoring Cunningham numbers: Pollard p-1: 4871 P57 6,396+ P. Zimmermann 4948 P57 11,260+ P. Zimmermann Special number field sieve by size of number factored: 4949 c248 2,1642M Aoki+Kida+Shimoyama+Sonoda+Ueda/CRYPTREC 4757 C244 2,809- Franke/Kleinjung/Bahr/CWI Special number field sieve by SNFS difficulty: 4949 c248 2,1642M Aoki+Kida+Shimoyama+Sonoda+Ueda/CRYPTREC 4983 c239 2,811- NFSNET" General number field sieve by size of number factored: 4924 C164 2,1826L Aoki+Kida+Shimoyama+Sonoda+Ueda/CRYPTREC 4701 C158 2,953+ F. Bahr + J. Franke + T. Kleinjung Elliptic curve method: 4830 P57 2,997- B. Dodson ECMNET 4917 P56 2,827+ K. Aoki ECMNET Largest penultimate prime factor (ultimate factor shown also): 4835 p105*p107 10,223- Dodson/AKL/Leyland/CWI 4677 p98*p122 2,727- Dodson/AKL/CWI First five holes in each table on November 8, 2004 2,739- c168 2,761- c189 2,781- c158 2,787- c204 2,791- c189 2,667+ c161 2,689+ c170 2,709+ c192 2,719+ c166 2,733+ c175 2,1294L c187 2,1322M c175 2,1334L c186 2,1342L c170 2,1342M c138 2,716+ c163 2,736+ c172 2,760+ c153 2,764+ c220 2,772+ c215 3,437- c151 3,443- c187 3,449- c175 3,461- c157 3,481- c201 3,424+ c156 3,436+ c194 3,437+ c190 3,452+ c195 3,463+ c200 5,307- c187 5,311- c173 5,313- c210 5,317- c194 5,319- c182 5,304+ c172 5,307+ c159 5,311+ c203 5,313+ c197 5,314+ c179 6,263- c196 6,281- c162 6,283- c173 6,293- c165 6,299- c155 6,263+ c186 6,269+ c135 6,271+ c195 6,274+ c191 6,283+ c193 7,253- c177 7,257- c192 7,259- c175 7,263- c161 7,269- c224 7,239+ c176 7,253+ c164 7,254+ c178 7,257+ c189 7,267+ c185 10,233- c162 10,239- c228 10,241- c229 10,257- c241 10,263- c216 10,226+ c197 10,229+ c164 10,232+ c160 10,236+ c193 10,238+ c152 11,217- c171 11,221- c135 11,227- c195 11,229- c217 11,233+ c181 11,208+ c185 11,212+ c201 11,218+ c192 11,220+ c147 11,224+ c194 12,227- c197 12,229- c242 12,233- c215 12,239- c255 12,241- c260 12,218+ c191 12,227+ c213 12,229+ c158 12,232+ c181 12,236+ c151