Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 87: | \[{18^{87}-1\over17}\] | 73 × 38281 × 1505548068007783<16> × 98800490511312118297<20> × 20423794322970766662747461449<29> × 23844678628322370113260816873780684279<38> |