Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 200: | \[{21^{200}-1\over20}\] | 23 × 52 × 11 × 13 × 17 × 41 × 101 × 19501 × 40841 × 56501 × 97241 × 185641 × 2031851 × 3441241 × 4141001 × 11093851 × 920421641 × 1166256601 × 35270582801<11> × 33360993558601<14> × 415710882920521<15> × 248303068144516751<18> × 27385718497004633851<20> × 2105812970476039816410905651801<31> × 35174788322661027467540897515852263605666386954957467123897302082814391146412401<80> |