n!! + 1
Table
Format: small prime × proven prime<size> × (probable prime)<size> × [composite]<size> × {unknown}<size>
| * 255: | \[255!!+1\] | 2 × 289489 × 18847691 × 772344109 × 7428583687103<13> × 2632999945211789861<19> × [39655878859541476101582304728571876555454215909186827559712412378629115946627999281618042348001477464755509008506625131891471597608876682858605682241953334284594039658600461107332925974493265119295821<200>] |