Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
99: | \[{20^{99}-1\over19}\] | 199 × 421 × 661 × 859 × 64008001 × 10778947368421<14> × 175462044485240500219<21> × 12992593428389191667383293584162419<35> × 445857960156220211502282409711073343103021<42> |