a(n) is n-th prime == -1 (mod 6n).

Terms

a(0) =5a(1) =23a(2) =71a(3) =167a(4) =179a(5) =431a(6) =461a(7) =863a(8) =863a(9) =839a(10) =1583a(11) =1511a(12) =1949a(13) =2099a(14) =2339a(15) =4127a(16) =4283a(17) =4751a(18) =4673a(19) =4919a(20) =5669a(21) =6599a(22) =8693a(23) =10079a(24) =7349a(25) =10607a(26) =12149a(27) =11087a(28) =12527a(29) =11159