Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 221: | \[{18^{221}-1\over17}\] | 17 × 79 × 521 × 30966079 × 29759719289<11> × 7563707819165039903<19> × 313769827308569076761943138309329491957488865716708510676198159679741233146114554095962256025982169985101728616729805168146431862210844811875600947759838574575111151650563697949172988824812261061841868068323319294354619202457264735569<234> |