Base 5 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
215: | \[{5^{215}-1\over4}\] | 11 × 71 × 431 × 1291 × 144982241 × 1644512641 × 1273316896028212631<19> × 172827552198815888791<21> × 1476723231934366547296339034741<31> × 14100541201973609621116340293054216571892383095715084191<56> |