a(n) = smallest number > 1 such that a(1)a(2)...a(n) - 1 is prime (or 1).

Terms

a(0) =2a(1) =2a(2) =2a(3) =3a(4) =2a(5) =4a(6) =2a(7) =3a(8) =6a(9) =4a(10) =5a(11) =5a(12) =5a(13) =10a(14) =4a(15) =3a(16) =5a(17) =8a(18) =22a(19) =13a(20) =14a(21) =2a(22) =5a(23) =5a(24) =2a(25) =20a(26) =9a(27) =9a(28) =24a(29) =5