List of champions for factoring Cunningham numbers: Special number field sieve by size of number factored: 5501 C307 2,1039- K.Aoki+J.Franke+T.Kleinjung+A.K.Lenstra+D.A.Osvik 5331 C274 6,353- Aoki+Kida+Shimoyama+Ueda Special number field sieve by SNFS difficulty: 5501 C307 2,1039- K.Aoki+J.Franke+T.Kleinjung+A.K.Lenstra+D.A.Osvik 5331 C274 6,353- Aoki+Kida+Shimoyama+Ueda General number field sieve by size of number factored: 5158 C176 11,281+ Aoki+Kida+Shimoyama+Ueda 5604 C165 6,383+ Mersenneforum+Womack Elliptic curve method: 5418 P67 10,381+ B. Dodson ECMNET 5135 P66 3,466+ B. Dodson ECMNET Largest penultimate prime factor (ultimate factor shown also): 5654 p127*p136 6,392+ Childers/Dodson 5331 p120*p155 6,353- Aoki+Kida+Shimoyama+Ueda First five holes in each table on November 7, 2008 2,827- c172 2,853- c212 2,857- c255 2,859- c203 2,863- c234 2,851+ c214 2,853+ c221 2,859+ c233 2,865+ c178 2,869+ c222 2,1598M c160 2,1606M c194 2,1618L c244 2,1642L c191 2,1646L c208 2,824+ c193 2,836+ c162 2,856+ c223 2,860+ c197 2,904+ c210 3,523- c233 3,527- c160 3,529- c237 3,551- c238 3,563- c199 3,508+ c188 3,509+ c171 3,521+ c181 3,538+ c177 3,548+ c197 5,347- c210 5,361- c189 5,383- c183 5,389- c231 5,391- c161 5,346+ c174 5,353+ c231 5,358+ c233 5,361+ c221 5,362+ c241 6,311- c168 6,335- c170 6,341- c224 6,343- c226 6,347- c249 6,302+ c173 6,304+ c216 6,314+ c209 6,316+ c210 6,317+ c225 7,277- c201 7,311- c225 7,323- c241 7,335- c219 7,337- c213 7,277+ c165 7,281+ c193 7,293+ c187 7,296+ c190 7,304+ c244 10,263- c216 10,269- c233 10,271- c214 10,277- c224 10,281- c210 10,236+ c193 10,241+ c175 10,244+ c215 10,248+ c199 10,268+ c219 11,227- c195 11,229- c217 11,233- c181 11,239- c246 11,241- c220 11,233+ c200 11,241+ c242 11,244+ c247 11,254+ c228 11,262+ c171 12,233- c215 12,239- c202 12,247- c209 12,257- c269 12,269- c205 12,232+ c181 12,253+ c169 12,254+ c230 12,256+ c228 12,259+ c194