Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 481: | \[{4^{481}-1\over3}\] | 223 × 1777 × 2731 × 8191 × 25781083 × 616318177 × 1484463163 × 138724733805016586033<21> × 5800976318060644948970424014255729<34> × 116082946165734700021832375583736205537<39> × 6891696701907972189990423390011944079746042979076780671011284119842734575263<76> × 96529160172936296910493238203560466707174118419318720105724235309272572481324977401<83> |