Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 249: | \[{21^{249}-1\over20}\] | 167 × 463 × 499 × 10957 × 756131 × 941221 × 13351381 × 41905574079441345694589359396489<32> × 23343519976297040387448341592997138604460338237413223529466429945751726176986579124533941307079<95> × 2173860862337982045334802960179813405517672855950877829757443471177425126106588003687946234524060021486858816229195692478179105662830101522605267272020279564800119518922843<172> |