Numbers k such that sigma(k)! - 1 is prime, where sigma is A000203.

Terms

a(0) =2a(1) =3a(2) =4a(3) =5a(4) =6a(5) =11a(6) =13a(7) =21a(8) =29a(9) =31a(10) =37a(11) =170a(12) =180a(13) =214a(14) =234a(15) =265a(16) =362a(17) =369a(18) =10734a(19) =14318a(20) =19679a(21) =19876a(22) =39636a(23) =48784a(24) =62517a(25) =76225a(26) =77277a(27) =83629a(28) =85519a(29) =90649