Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 249: | \[{4^{249}-1\over3}\] | 3 × 7 × 167 × 499 × 1163 × 2657 × 155377 × 1621324657 × 13455809771<11> × 9202419446683<13> × 57912614113275649087721<23> × 3388098290567587377052016525627948593<37> × 8241594690167137359552274418432855740327<40> |