Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 287: | \[{20^{287}-1\over19}\] | 29 × 71 × 739 × 4019 × 32719 × 833449 × 4356661 × 788985829969499330639<21> × 19850094536448035972954342201<29> × [115019575644379652041994614268977104412719237054998735476627833792070397179443406639774789253976671665869312044360621999564285864688999596458371058957460294853357906686339986459982764693123503732695319428036625652405689095232844270673547904033695937224979439587499480996356396360576493495681210891<297>] |