a(n) = prime(prime(prime(A028815(n) - 1) - 1) - 1) - 1.

Terms

a(0) =1a(1) =2a(2) =12a(3) =106a(4) =238a(5) =612a(6) =1020a(7) =1732a(8) =2088a(9) =2902a(10) =4336a(11) =5278a(12) =7102a(13) =8500a(14) =9282a(15) =10566a(16) =12640a(17) =15268a(18) =15678a(19) =19488a(20) =21142a(21) =22062a(22) =24766a(23) =27430a(24) =30108a(25) =33892a(26) =37056a(27) =38706a(28) =40786a(29) =41980