Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
151: | \[{4^{151}-1\over3}\] | 18121 × 55871 × 165799 × 2332951 × 18717738334417<14> × 7289088383388253664437433<25> × 50834050824100779677306460621499<32> |