Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
481: | \[2^{481}-1\] | 223 × 8191 × 616318177 × 138724733805016586033<21> × 5800976318060644948970424014255729<34> × 6891696701907972189990423390011944079746042979076780671011284119842734575263<76> |