Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 273: | \[{21^{273}-1\over20}\] | 43 × 79 × 463 × 547 × 631 × 1093 × 1171 × 3319 × 4789 × 6427 × 20749 × 55147 × 189437 × 1985257 × 227633407 × 516094151 × 424277387218231<15> × 80459337199345300130638393<26> × 780822438421787911002783931<27> × 35381269315942497678572657090020747<35> × 64217370090877823505293705129529905363070886592641<50> × 4264091474110761334946377629947327910839217826620223120485043<61> × 498781338000312073562645370699142335995279921484122232195724922163118040842963447<81> |