a(0)=0, a(1)=1, a(n)=(a(n-1) XOR n) + a(n-2).

Terms

a(0) =0a(1) =1a(2) =3a(3) =1a(4) =8a(5) =14a(6) =16a(7) =37a(8) =61a(9) =89a(10) =144a(11) =244a(12) =392a(13) =633a(14) =1023a(15) =1641a(16) =2680a(17) =4306a(18) =6968a(19) =11261a(20) =18209a(21) =29489a(22) =47688a(23) =77200a(24) =124880a(25) =202073a(26) =326931a(27) =528993a(28) =855952a(29) =1384942