Generalized nim sum n + n in base 8.

Terms

a(0) =0a(1) =2a(2) =4a(3) =6a(4) =0a(5) =2a(6) =4a(7) =6a(8) =16a(9) =18a(10) =20a(11) =22a(12) =16a(13) =18a(14) =20a(15) =22a(16) =32a(17) =34a(18) =36a(19) =38a(20) =32a(21) =34a(22) =36a(23) =38a(24) =48a(25) =50a(26) =52a(27) =54a(28) =48a(29) =50