Numbers k such that (k! - 2)/2 is a prime.

Terms

a(0) =3a(1) =4a(2) =5a(3) =6a(4) =9a(5) =31a(6) =41a(7) =373a(8) =589a(9) =812a(10) =989a(11) =1115a(12) =1488a(13) =1864a(14) =1918a(15) =4412a(16) =4686a(17) =5821a(18) =13830