n!! + 1
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
155: | \[155!!+1\] | 22 × 167 × 61027 × 24121168380689391439<20> × 221990947242589110330747119945866924668232992163340830452015822807951537733424959903605415398652006830333694169<111> |