a(1) = 2, a(2) = 3; for n >= 2, a(n+1) is smallest prime factor of (Product_{k = 1..n} a(k)) - 1.

Terms

a(0) =2a(1) =3a(2) =5a(3) =29a(4) =11a(5) =7a(6) =13a(7) =37a(8) =32222189a(9) =131a(11) =31a(12) =197a(13) =19a(14) =157a(15) =17a(16) =8609a(17) =1831129a(18) =35977a(20) =487a(21) =10253a(22) =1390043a(24) =25319167a(25) =9512386441a(26) =85577a(27) =1031a(28) =3650460767a(29) =107a(30) =41a(31) =811a(32) =15787