Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 204: | \[{4^{204}-1\over3}\] | 3 × 5 × 7 × 13 × 172 × 103 × 137 × 241 × 307 × 409 × 953 × 2143 × 2857 × 3061 × 6529 × 8161 × 11119 × 13669 × 26317 × 43691 × 131071 × 354689 × 40932193 × 1326700741 × 1467129352609<13> × 2879347902817<13> × 737539985835313<15> |