Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 303: | \[2^{303}-1\] | 7 × 607 × 7432339208719<13> × 341117531003194129<18> × 1512768222413735255864403005264105839324374778520631853993<58> |