Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 385: | \[2^{385}-1\] | 23 × 31 × 71 × 89 × 127 × 881 × 3191 × 55441 × 122921 × 201961 × 1971764055031<13> × 581283643249112959<18> × 31055341681190444478126719755965134571151473925765532041<56> |