Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
285: | \[2^{285}-1\] | 7 × 31 × 151 × 191 × 32377 × 524287 × 1212847 × 420778751 × 30327152671<11> × 1491477035689218775711<22> × 25349242986637720573561<23> |