n!!! - 1
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
255: | \[255!!!-1\] | 547 × 4691 × 123143 × 155964774541<12> × 19293102329521086858349097<26> × 10641882774204501247981481958985469795835226180591342527190748229444404000543915282846110829643672800811239866908726609517<122> |