Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
78: | \[{20^{78}-1\over19}\] | 32 × 7 × 79 × 127 × 421 × 1171 × 2081 × 2549 × 3121 × 142559 × 1340743 × 9690539 × 571945141 × 735408649 × 22969682841393367<17> × 172311318287603732461390609<27> |