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 6315 C342 2,1171- J.Bos+T.Kleinjung+A.K.Lenstra Special number field sieve by SNFS difficulty: 6297 C355 2,1193- J.Bos+T.Kleinjung+A.K.Lenstra 6315 C342 2,1171- J.Bos+T.Kleinjung+A.K.Lenstra General number field sieve by size of number factored: 6319 C221 3,697+ NFS@Home 6269 C216 3,766+ 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 First five holes in each table on May 10, 2016 2,1207- c337 2,1213- c297 2,1217- c248 2,1219- c322 2,1229- c284 2,1009+ c244 2,1019+ c223 2,1033+ c255 2,1037+ c209 2,1063+ c281 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- c205 3,619+ c272 3,631+ c219 3,632+ c220 3,643+ c210 3,647+ c277 5,431- c266 5,449- c271 5,473- c268 5,481- c302 5,493- c277 5,422+ c235 5,424+ c282 5,431+ c292 5,436+ c278 5,439+ c250 6,383- c264 6,391- c274 6,401- c274 6,421- c281 6,431- c321 6,389+ c242 6,391+ c260 6,394+ c273 6,397+ c231 6,404+ c266 7,353- c263 7,359- c224 7,361- c290 7,367- c252 7,373- c204 7,353+ c241 7,356+ c207 7,359+ c278 7,367+ c301 7,373+ c303 10,323- c271 10,337- c268 10,343- c238 10,353- c328 10,365- c288 10,302+ c289 10,304+ c282 10,311+ c223 10,313+ c230 10,323+ c242 11,283- c268 11,293- c300 11,307- c289 11,311- c251 11,313- c273 11,283+ c258 11,292+ c259 11,293+ c212 11,298+ c243 11,302+ c225 12,271- c234 12,277- c285 12,281- c235 12,283- c244 12,289- c248 12,271+ c250 12,274+ c213 12,289+ c265 12,293+ c303 12,298+ c305