Numbers n such that n!! + 2 is prime.

Terms

a(0) =0a(1) =1a(2) =3a(3) =5a(4) =7a(5) =9a(6) =21a(7) =23a(8) =27a(9) =57a(10) =75a(11) =103a(12) =169a(13) =219a(14) =245a(15) =461a(16) =695a(17) =1169a(18) =3597a(19) =3637a(20) =7495a(21) =27743a(22) =28799a(23) =32501