Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
40: | \[{18^{40}-1\over17}\] | 53 × 11 × 13 × 19 × 41 × 113 × 881 × 929 × 2711 × 9041 × 15101 × 145501 × 137841514501966721<18> |