Base 3 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 191: | \[{3^{191}-1\over2}\] | 383 × 311713 × 9593931911<10> × 5890868591760365434332005074929710400548909181468214858888800348369500317<73> |