Base 18 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| 273: | \[{18^{273}-1\over17}\] | 74 × 79 × 449 × 521 × 8009 × 16927 × 21841 × 80207 × 7424759473<10> × 29759719289<11> × 107888439023<12> × 156107192084257<15> × 170258429679493134487<21> × 119941938141663914560035192594531172177434180409487272285332931752751273<72> × 359260814189773531620491945236157341040255562668193879928254035212354363284846624020165848111455399174041838652490606891299571212196336513540556136150011287447375468385739434313<177> |