Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
54: | \[{20^{54}-1\over19}\] | 34 × 7 × 109 × 127 × 307 × 421 × 4483 × 69481 × 64008001 × 99672121 × 879338701 × 1794112741 × 298114935351301<15> |