a(1)=1; for n>=2, a(n) = the largest prime dividing n*a(n-1) + 1.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =3a(5) =19a(6) =67a(7) =179a(8) =31a(9) =311a(10) =59a(11) =709a(12) =419a(13) =5867a(14) =557a(15) =2971a(16) =61a(17) =157a(18) =373a(19) =829a(20) =1741a(21) =38303a(22) =2381a(23) =1039a(24) =191a(25) =4967a(26) =13411a(27) =375509a(28) =418837a(29) =966547