Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 103: | \[{21^{103}-1\over20}\] | 4327 × 49853 × 3578319942163234761948197423711625937273928656180280573469957211934243130134304207939291415435034091514822796033427258153670673<127> |