Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 67: | \[{28^{67}-1\over27}\] | 39629149774235919086803410436533512071<38> × 8515488777545809574252900816572650580619264994750394645483<58> |