Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 216: | \[{21^{216}-1\over20}\] | 23 × 11 × 13 × 17 × 19 × 37 × 61 × 73 × 109 × 163 × 199 × 421 × 463 × 613 × 1693 × 3181 × 5077 × 7993 × 17497 × 97241 × 816769 × 4779433 × 85775383 × 518118697 × 808208209 × 14697355609<11> × 4344847859197<13> × 7429452749713<13> × 7101932659132249<16> × 81967288802253121<17> × 360697466924286697<18> × 30399041735797255948625080033<29> × 1103447100998503280657719551313<31> × 44358853414017625659980074499682084926190043494844801<53> |