Base 2 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 449: | \[2^{449}-1\] | 1256303 × 6871197486841<13> × 3578620616468306981503<22> × 526385733768051189441947168504909159<36> × 89396693392545895668303801721053258296972567022618106513441<59> |