Numbers k such that k!! - 2^k is prime.

Terms

a(0) =9a(1) =13a(2) =21a(3) =25a(4) =27a(5) =35a(6) =41a(7) =53a(8) =63a(9) =81a(10) =123a(11) =333a(12) =381a(13) =413a(14) =1187a(15) =2265a(16) =3153a(17) =4211a(18) =4887a(19) =7359a(20) =14161a(21) =14643a(22) =17299a(23) =22107a(24) =31487a(25) =40235a(26) =46711