| History of Cunningham Chain length 18 | |||
| Initial prime number | Digits | When | Discoverer |
|---|---|---|---|
| 1st kind | |||
| 214325014495971624590189129 | 27 | 16 Mar 2026 | Nenad Mićić |
| 106103983461039119546815109 | 27 | 14 Mar 2026 | Nenad Mićić |
| 776208125345634679522109 | 24 | 2021 | John Armitage |
| 2nd kind | |||
| 658189097608811942204322721 | 27 | 8 Mar 2014 | Raanan Chermoni, Jaroslaw Wroblewski |
| 182927793839529342111307801 | 27 | 8 Mar 2014 | Raanan Chermoni, Jaroslaw Wroblewski |
| 117302256313688977973793781 | 27 | 8 Mar 2014 | Raanan Chermoni, Jaroslaw Wroblewski |
| 868594057941691288178401 | 24 | 2021 | John Armitage |
| 773377687199227745520601 | 24 | 2021 | John Armitage |