Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 289: | \[{4^{289}-1\over3}\] | 43691 × 72251 × 79187 × 131071 × 1077971 × 12761663 × 18360250452977<14> × 197766803208315851<18> × 179058312604392742511009<24> × 338858733065598401355195539629373089<36> × 3320934994356628805321733520790947608989420068445023<52> |