Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 131: | \[{20^{131}-1\over19}\] | 28559 × 42826820062834429<17> × 87138888519025909<17> × 7828769974104026860693944259<28> × 17358908895752663637684695959931846281734452761<47> × 989211218764465041890284072238784671227769462489155618721<57> |