Base 15 Repunits
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
77: | \[{15^{77}-1\over14}\] | 7 × 67 × 463 × 2333 × 5237 × 8537 × 1743463 × 28095816025663<14> × 233231979450578549516941109533238047237736577451339331<54> |