Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 160: | \[{21^{160}-1\over20}\] | 25 × 5 × 11 × 13 × 17 × 41 × 241 × 1217 × 2689 × 9521 × 31873 × 35201 × 40841 × 62897 × 97241 × 185641 × 300673 × 3441241 × 22995281 × 33534961 × 920421641 × 3184193681 × 6857635489<10> × 363230092241<12> × 415710882920521<15> × 742519225358081<15> × 160240451081797786982584096011519912592914325275939917098602236161<66> |