Base 20 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 181: | \[{20^{181}-1\over19}\] | 5431 × 1679681 × 45404357846358829<17> × 3894677162387392434645730540515184763824843975621564783040563384365388557244951108331157076580009925870773473325632383238559696983211619433738097344800138964567088742963904202858499097196480895839591908466159<208> |