Numbers k such that k! + (k+1)! - 1 is prime.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =13a(6) =14a(7) =17a(8) =27a(9) =28a(10) =33a(11) =39a(12) =103a(13) =115a(14) =205a(15) =291a(16) =1431a(17) =1532a(18) =1710a(19) =1937a(20) =3901a(21) =3981a(22) =4682a(23) =6569a(24) =20266a(25) =20662