Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 74: | \[{28^{74}-1\over27}\] | 29 × 149 × 223 × 1481 × 20129 × 36129368689<11> × 1004690609843<13> × 362872981217703889717460874623<30> × 12034188740195053379860324023109474023287<41> |