Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 260: | \[{21^{260}-1\over20}\] | 22 × 5 × 11 × 132 × 17 × 41 × 53 × 79 × 131 × 521 × 32969 × 40841 × 101089 × 185641 × 189437 × 443431 × 516094151 × 920421641 × 42992409721<11> × 85864930061<11> × 7021471715414521<16> × 23509884574335185209<20> × 101619538800983513441<21> × 128789956824244730223808008541<30> × 1433993498064013499085064988761<31> × 57931461377789233256346069736652710022521<41> × 12600830975010449603387809542079615686511399481<47> × 47999819885150422820855221255204479443163906801765079421<56> |