Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 241: | \[{4^{241}-1\over3}\] | 2411 × 22000409 × 10411181203<11> × 15059828108442641<17> × 3115949925222900514664736941746248477210667<43> × 160619474372352289412737508720216839225805656328990879953332340439<66> |