Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 401: | \[{4^{401}-1\over3}\] | 18885983617<11> × 856971565399<12> × 2136958965524920285681<22> × 3178641606717935496778334833<28> × 594538100848945223169882301931953<33> × 24789994689980013078275217373572023257787<41> × 1156776348417160383928286284678419338772193<43> × 4743358775443804666040010704534780418840545962266329593<55> |