Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 353: | \[2^{353}-1\] | 931921 × 2927455476800301964116805545194017<34> × 6725414756111955781503880188940925566051960039574573675843402666863<67> |