Base 4 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 290: | \[{4^{290}-1\over3}\] | 52 × 11 × 31 × 41 × 59 × 233 × 1103 × 2089 × 17401 × 168781 × 3033169 × 7553921 × 107367629 × 536903681 × 244716883381<12> × 3902095192430070721<19> × 999802854724715300883845411<27> × 12004541501954811085302214141<29> × 2679895157783862814690027494144991<34> |