Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 307: | \[{4^{307}-1\over3}\] | 14608903 × 85798519 × 1249678499 × 23487583303<11> × 78952752017<11> × 4315199443523<13> × 210708825063558235331<21> × 76490150923395684178472404003401860286655314439889<50> × 112177476474470525577861298937835338545723093134076373561<57> |