Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 387: | \[2^{387}-1\] | 7 × 73 × 431 × 9719 × 2099863 × 11492353 × 22763003975641<14> × 6834040335349578249140287<25> × 11053036065049294753459639<26> × 3548950581098263559084652467359<31> |