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

Terms

a(0) =1a(1) =2a(2) =2a(3) =2a(4) =9a(5) =2a(6) =13a(7) =2a(8) =21a(9) =15a(10) =21a(11) =23a(12) =21a(13) =23a(14) =33a(15) =31a(16) =31a(17) =35a(18) =33a(19) =37a(20) =45a(21) =39a(22) =45a(23) =49a(24) =39a(25) =39a(26) =51a(27) =55a(28) =59a(29) =57