a(n) = prime(2n-1) mod prime(n).

Terms

a(0) =0a(1) =2a(2) =1a(3) =3a(4) =1a(5) =5a(6) =7a(7) =9a(8) =13a(9) =9a(10) =11a(11) =9a(12) =15a(13) =17a(14) =15a(15) =21a(16) =19a(17) =27a(18) =23a(19) =25a(20) =33a(21) =33a(22) =31a(23) =33a(24) =33a(25) =31a(26) =35a(27) =43a(28) =51a(29) =51