Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
151: | \[{20^{151}-1\over19}\] | 4229 × 25423286839<11> × 337949154488989<15> × 309697263932086039828104882838712610494719<42> × 5232204626707648449380809177494756211834928582631809<52> × 25517193589776565228397705061409969056835464082241004608797977404080980589<74> |