Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 283: | \[{4^{283}-1\over3}\] | 1699 × 9623 × 62827 × 2486265371 × 68492481833<11> × 67535788803713<14> × 289032286755051820954283562071395404701830115983581457<54> × 23579543011798993222850893929565870383844167873851502677311057483194673<71> |