Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 515: | \[{4^{515}-1\over3}\] | 11 × 31 × 1031 × 989831 × 2550183799 × 415141630193<12> × 8142767081771726171<19> × 3976656429941438590393<22> × 48111154791914771769582354405627641<35> × 960954217134424245898328814050043401<36> × 1925631536827398342750945451754630611<37> × 10378785997959707787746618479652152430027101880522681<53> × 347915763440394715608132793485938330295552666256070916974339749248185891333591<78> |