List of champions for factoring Cunningham numbers: Quadratic sieve method: 2766 C106 2,353+ A. K. Lenstra & M. Manasse & al. with many computers 2910 C103 2,361+ A. K. Lenstra & M. Manasse & al. with many computers 2847 C103 10,122+ A. K. Lenstra & M. Manasse & al. with many computers Number field sieve: 2894 C122 7,149+ A. K. Lenstra & M. Manasse with several computers 2880 C108 2,373+ A. K. Lenstra & M. Manasse with several computers 2906 C107 3,239- A. K. Lenstra & M. Manasse with several computers Elliptic curve method: 2859 P38 11,118+ A. K. Lenstra & M. Manasse with several computers 2545 P36 2,706M A. K. Lenstra & M. Manasse with several computers Largest penultimate prime factor (ultimate factor shown also): 2894 p56*p66 7,149+ A. K. Lenstra & M. Manasse with several computers 2880 p48*p60 2,373+ A. K. Lenstra & M. Manasse with several computers Table First four holes in each table on October 4, 1989: 2- 2,445- c103 2,449- c95 2,467- c133 2,479- c127 2+,odd 2,427+ c98 2,439+ c105 2,443+ c105 2,449+ c123 2LM 2,722M c103 2,794L c104 2,802L c107 2,802M c104 2+,4k 2,428+ c114 2,436+ c96 2,460+ c106 2,484+ c111 3- 3,227- c98 3,241- c115 3,251- c117 3,257- c118 3+ 3,236+ c92 3,263+ c105 3,269+ c123 3,271+ c91 5- 5,169- c105 5,187- c106 5,201- c93 5,211- c94 5+ 5,167+ c104 5,184+ c91 5,187+ c105 5,188+ c96 6- 6,149- c108 6,151- c105 6,163- c124 6,173+ c119 6+ 6,155+ c94 6,164+ c125 6,169+ c101 6,172+ c99 7- 7,163- c101 7,167- c111 7,169- c132 7,173- c146 7+ 7,146+ c111 7,160+ c95 7,163+ c117 7,164+ c136 10- 10,151- c139 10,157- c132 10,163- c163 10,167- c142 10+ 10,134+ c98 10,142+ c116 10,149+ c123 10,151+ c112 11- 11,131- c134 11,145- c113 11,151- c139 11,157- c126 11+ 11,122+ c92 11,125+ c96 11,127+ c120 11,131+ c129 12- 12,121- c94 12,127- c126 12,133- c104 12,137- c123 12+ 12,118+ c110 12,119+ c100 12,125+ c96 12,127+ c99 Ten ``Most Wanted'' Factorizations 1. 2,512+ C148 6. 10,151- C139 2. 2,1024+ C291 7. 10,142+ C116 3. 5,256+ C134 8. 3,241- C115 4. 2,428+ C114 9. 6,149- C108 5. 2,467- C133 10. 12,118+ C110 Twenty-Four ``More Wanted'' Factorizations 2,445- C103 2,436+ C96 7,160+ C95 2,449- C95 3,227- C98 10,134+ C98 2,427+ C98 3,236+ C92 11,122+ C92 2,439+ C105 5,169- C105 11,125+ C96 2,443+ C105 5,167+ C104 11,127+ C120 2,449+ C123 6,151- C105 12,121- C94 2,722M C103 6,155+ C94 12,119+ C100 2,794L C104 7,146+ C111 12,125+ C96