n!!!! + 1
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
226: | \[226!!!!+1\] | 383 × 4253 × 2490509337331<13> × 115130993245577<15> × 808122540531732359<18> × 166282499671732144825224924243002088331774184228278013715703<60> |