Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 28: | \[{21^{28}-1\over20}\] | 22 × 11 × 13 × 17 × 29 × 43 × 631 × 3319 × 3697 × 81867661 × 68454248717<11> |
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 28: | \[{21^{28}-1\over20}\] | 22 × 11 × 13 × 17 × 29 × 43 × 631 × 3319 × 3697 × 81867661 × 68454248717<11> |