Numbers k such that k!!-4 is prime.

Terms

a(0) =5a(1) =7a(2) =9a(3) =11a(4) =13a(5) =15a(6) =19a(7) =25a(8) =35a(9) =79a(10) =81a(11) =105a(12) =171a(13) =243a(14) =271a(15) =295a(16) =355a(17) =523a(18) =591a(19) =1211a(20) =3073a(21) =11157a(22) =12887a(23) =19825