Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
265: | \[2^{265}-1\] | 31 × 6361 × 69431 × 20394401 × 29324808311<11> × 197748738449921<15> × 36614110124735294634435619027766763481<38> |