Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 437: | \[2^{437}-1\] | 47 × 178481 × 524287 × 3198841 × 5579617 × 6203145044672921<16> × 728853407707467208421993458966504139019157860437186335406130262344738292438484569798131887<90> |