Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
54: | \[{18^{54}-1\over17}\] | 73 × 19 × 73 × 307 × 991 × 23761 × 34327 × 253369 × 465841 × 1464049 × 4464073 × 31865908033<11> × 1234749313729<13> |