Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 146: | \[{4^{146}-1\over3}\] | 5 × 293 × 439 × 1753 × 9929 × 2298041 × 9361973132609<13> × 649301712182209<15> × 1795918038741070627<19> × 9444732965601851473921<22> |