List of recent champions for factoring Cunningham numbers: Special number field sieve by size of number factored: 6297 C355 2,1193- J.Bos+T.Kleinjung+A.K.Lenstra 6287 C331 2,1153- J.Bos+T.Kleinjung+A.K.Lenstra 6285 C327 2,1129- J.Bos+T.Kleinjung+A.K.Lenstra 6132 C320 2,1061- NFS@Home 5501 C307 2,1039- K.Aoki+J.Franke+T.Kleinjung+A.K.Lenstra+D.A.Osvik Special number field sieve by SNFS difficulty: 6297 C355 2,1193- J.Bos+T.Kleinjung+A.K.Lenstra 6288 C309 2,1159- J.Bos+T.Kleinjung+A.K.Lenstra 6287 C331 2,1153- J.Bos+T.Kleinjung+A.K.Lenstra 6285 C327 2,1129- J.Bos+T.Kleinjung+A.K.Lenstra 6283 C251 2,1081- J.Bos+T.Kleinjung+A.K.Lenstra 6132 C320 2,1061- NFS@Home 6174 C218 2,1049+ NFS@Home General number field sieve by size of number factored: 6269 C216 3,766+ NFS@Home 6216 C212 10,770M NFS@Home Elliptic curve method: 6208 P83 7,337+ R. Propper 6135 P79 11,306+ S. Wagstaff Largest penultimate prime factor (ultimate factor shown also): 6302 p146.p156 2,1109- J.Bos+T.Kleinjung+A.K.Lenstra 6132 p143*p177 2,1061- NFS@Home 6285 p139*p188 2,1129- J.Bos+T.Kleinjung+A.K.Lenstra 6249 p134*p141 2,1906M R. Propper 6116 p133*p139 5,433+ NFS@Home First five holes in each table on September 20, 2014 2,991- c264 2,1117- c332 2,1123- c321 2,1147- c263 2,1171- c342 2,983+ c236 2,989+ c249 2,991+ c224 2,1009+ c244 2,1019+ c223 2,1934M c225 2,1954M c246 2,1982M c249 2,2006M c276 2,2018L c240 2,1028+ c241 2,1052+ c300 2,1072+ c271 2,1076+ c238 2,1084+ c318 3,617- c277 3,619- c207 3,661- c316 3,667- c275 3,671- c271 3,619+ c272 3,631+ c219 3,632+ c220 3,643+ c210 3,647+ c277 5,419- c224 5,431- c266 5,449- c271 5,473- c268 5,481- c302 5,419+ c236 5,422+ c235 5,424+ c282 5,431+ c292 5,436+ c278 6,383- c264 6,391- c274 6,401- c274 6,421- c281 6,431- c321 6,376+ c224 6,389+ c242 6,391+ c260 6,394+ c273 6,397+ c297 7,353- c263 7,359- c224 7,361- c290 7,367- c252 7,373- c267 7,346+ c251 7,353+ c241 7,356+ c207 7,359+ c278 7,367+ c301 10,323- c271 10,337- c268 10,341- c226 10,343- c238 10,353- c328 10,298+ c267 10,302+ c289 10,304+ c282 10,311+ c223 10,313+ c230 11,283- c268 11,293- c300 11,307- c289 11,311- c323 11,313- c273 11,283+ c258 11,292+ c259 11,293+ c212 11,298+ c243 11,302+ c225 12,269- c205 12,271- c234 12,277- c285 12,281- c235 12,283- c244 12,271+ c250 12,274+ c213 12,283+ c194 12,284+ c252 12,289+ c265