Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 268: | \[{4^{268}-1\over3}\] | 5 × 17 × 269 × 75041 × 7327657 × 15152453 × 42875177 × 193707721 × 2559066073 × 761838257287<12> × 6713103182899<13> × 9739278030221<13> × 333808138537249<15> × 1113767094422199900605896348724787045161997478687751948513969<61> |