Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 167: | \[{4^{167}-1\over3}\] | 2349023 × 79638304766856507377778616296087448490695649<44> × 62357403192785191176690552862561408838653121833643<50> |