Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 149: | \[{4^{149}-1\over3}\] | 1193 × 650833 × 38369587 × 86656268566282183151<20> × 8235109336690846723986161<25> × 7984559573504259856359124657<28> |