Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 197: | \[{20^{197}-1\over19}\] | 1314779 × 106562961720350371<18> × [7545647337862079438098326953721860355021632978730325798516918899402625299998521692390626086159513970841071222702264989562248459021451664244126946367257302857699598804894262278380843306458104076109075896136541515542789277722175321269<232>] |