Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 159: | \[{4^{159}-1\over3}\] | 3 × 7 × 107 × 6043 × 6361 × 6679 × 69431 × 13960201 × 20394401 × 540701761 × 229890275929<12> × 28059810762433<14> × 4475130366518102084427698737<28> |