Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 105: | \[{21^{105}-1\over20}\] | 5 × 43 × 211 × 463 × 631 × 1471 × 3319 × 4789 × 6427 × 9391 × 18181 × 40841 × 4149601 × 20028751 × 81090871 × 227633407 × 3987476221 × 421503321597121<15> × 5124240195826801224421<22> × 1855106691418101398774071<25> |