Nimsum n + 4.

Terms

a(0) =4a(1) =5a(2) =6a(3) =7a(4) =0a(5) =1a(6) =2a(7) =3a(8) =12a(9) =13a(10) =14a(11) =15a(12) =8a(13) =9a(14) =10a(15) =11a(16) =20a(17) =21a(18) =22a(19) =23a(20) =16a(21) =17a(22) =18a(23) =19a(24) =28a(25) =29a(26) =30a(27) =31a(28) =24a(29) =25