List of champions for factoring Cunningham numbers: Continued fraction method: 1692 C63 5,171+ K. McCurdy & M. C. Wunderlich on the MPP 1602 C62 3,204+ J. W. Smith & S. S. Wagstaff, Jr. on the EPOC SPAR: 1066 C60 3,131+ A. O. L. Atkin & N. W. Rickert on a large IBM 941 C59 12,59- A. O. L. Atkin & N. W. Rickert on a large IBM Pollard p-1: 5267 P58 2,2098M P. Zimmermann 4871 P57 6,396+ P. Zimmermann p-1/FFT: 2590 P28 2, 733+ R. Silverman on an Alliant 2550 P27 2,1008+ R. Silverman on an Alliant p+1: 0 P21 2,439- R. P. Brent on a Univac 1100/82 5 P20 2,509- R. P. Brent on a Univac 1100/82 Brent-Pollard rho: 1343 P19 2,2386L H. Dubner on a special processor 1254 P19 2,1049- H. Dubner on a special processor 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: 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 Hybrid Special/General number field sieve by size of number factored: 4083 C123 2,1155+ CWI 4036 C121 2,1650L CWI 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): 5331 p120*p155 6,353- Aoki+Kida+Shimoyama+Ueda 5557 p113*p125 3,499+ Kruppa+Silverman+Leyland/Bahr/Franke/Kleinjung First five holes in each table on July 7, 2008 2,823- c197 2,827- c172 2,853- c212 2,857- c255 2,859- c203 2,823+ c229 2,851+ c214 2,853+ c221 2,859+ c233 2,865+ c178 2,1538M c208 2,1586L c156 2,1598L c171 2,1598M c160 2,1606M c194 2,824+ c193 2,832+ c175 2,836+ c162 2,856+ c223 2,860+ c197 3,523- c233 3,527- c160 3,529- c237 3,547- c242 3,551- c238 3,508+ c188 3,509+ c171 3,517+ c220 3,521+ c181 3,538+ c177 5,331- c187 5,341- c175 5,347- c210 5,361- c189 5,383- c183 5,331+ c193 5,346+ c174 5,353+ c231 5,358+ c233 5,361+ c221 6,311- c168 6,313- c227 6,335- c170 6,341- c224 6,343- c226 6,302+ c173 6,304+ c216 6,314+ c209 6,316+ c210 6,317+ c225 7,277- c201 7,311- c225 7,313- c248 7,319- c233 7,323- c241 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 10,247+ c201 10,248+ c199 11,227- c195 11,229- c217 11,233- c181 11,239- c246 11,241- c220 11,226+ c222 11,233+ c200 11,241+ c242 11,244+ c247 11,254+ c228 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