Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 284: | \[{21^{284}-1\over20}\] | 22 × 11 × 13 × 17 × 853 × 493509073 × 7532230393<10> × 826880829487<12> × 172132091765842074983<21> × 6912925952086714539251625713<28> × 110556144297525239244017467747224789359885811468762753179<57> × 2409031482389671650882277254771562219466455949802660831413381<61> × 20037565550989336813681244886167554272648043801186036102071486379565020360520375260760685105005446835732079517490524778710411645976598566800120419135922180555524341940807469<173> |