Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 421: | \[{4^{421}-1\over3}\] | 4211 × 614002928307599<15> × 32983076027612611<17> × 12996623037294014057591212988182028173802393910829199191218499846140826287303581583005154159743906016002531<107> × 8819779591697258388298117725624832271141577326602771028307143781815455970700534027206522451123308835472505327249<112> |