Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 68: | \[{28^{68}-1\over27}\] | 5 × 29 × 137 × 157 × 239 × 613 × 2347 × 8807 × 33049 × 45508138747<11> × 148020807352107352204781<24> × 4493911532793397608107303677360753164689<40> |