Base 21 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
46: | \[{21^{46}-1\over20}\] | 2 × 11 × 47 × 277 × 461 × 599 × 691 × 19597 × 2215825387044753577<19> × 139870566115103282847737<24> |