Base 28 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 87: | \[{28^{87}-1\over27}\] | 3 × 59 × 271 × 77241733 × 5506203727<10> × 582595509837473004489665028935473297399<39> × 2490984281800796713523237526645659080993083834467855653648162831<64> |