Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 317: | \[2^{317}-1\] | 9511 × 587492521482839879<18> × 4868122671322098041565641<25> × 9815639231755686605031317440031161584572466128599<49> |