Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 355: | \[{4^{355}-1\over3}\] | 11 × 31 × 228479 × 48544121 × 56409643 × 212885833 × 121932688511<12> × 13952598148481<14> × 15524635883992211<17> × 182013944029916253984850599290949064721089587458906809918552581277361<69> × 8223125624363292839815514592697905768406610797334099385507174111379292321<73> |