a(0) = 0, a(n) = a(n-1) XOR n.

Terms

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