n!!!! + 1
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 260: | \[260!!!!+1\] | 131 × 111427 × [769073694025178747857411515692406353370077827873526384935404759282147123736921910821507727021690810019354038816514999002873<123>] |