Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 401: | \[2^{401}-1\] | 856971565399<12> × 2136958965524920285681<22> × 594538100848945223169882301931953<33> × 4743358775443804666040010704534780418840545962266329593<55> |