Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 645: | \[{21^{645}-1\over20}\] | 5 × 211 × 463 × 1033 × 9391 × 13331 × 18181 × 40841 × 68371 × 78691 × 95461 × 1135201 × 32108273175191<14> × 222756144763231<15> × 353955909257491<15> × 5124444692411823514711231<25> × 7953436401867987800552310336799<31> × 35842614220783025524408588074144786493150233831596714503<56> × 119000957796440462394517307940919912228603619382831962610320796808847023<72> × [13562599955176353510116932638420458071565457554655268437338931646916920143663769327768863717647580420852895912822766242059684418900050381749616225265431658758039362408990835103490754726347731<191>] × [2077812585875632139576755934559539839524674068871725486163361331527698600622639281921215868054148426724288011418205908537497674083132331355322774012240897117932819064315067024414497189958118795936534782574759944894544869514106017975882360200473581807321808835572783035173361856029678288845552308918004098733941993299190982719629502095113047313237314062841845923281527254210094409541700330121<391>] |