Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
77: | \[{20^{77}-1\over19}\] | 29 × 71 × 32719 × 10778947368421<14> × 11591111347512862858060061<26> × 94492701984716091424823399007224633473246602866536721<53> |