Base 22 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
51: | \[{22^{51}-1\over21}\] | 3 × 132 × 239 × 613 × 74729519 × 176634767651<12> × 29084130008763268099<20> × 485564174838252486973<21> |