Base 3 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
205: | \[{3^{205}-1\over2}\] | 112 × 83 × 6971 × 31981 × 2526913 × 86950696619<11> × 65601426257068882740808329269766819608728424724067187242117750270751<68> |