Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 279: | \[2^{279}-1\] | 7 × 73 × 16183 × 34039 × 1437967 × 2147483647 × 833732508401263<15> × 658812288653553079<18> × 2034439836951867299888617<25> |