a(n) = a(n-1) XOR (a(n-2)*3).

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =1a(5) =7a(6) =4a(7) =17a(8) =29a(9) =46a(10) =121a(11) =243a(12) =408a(13) =833a(14) =1929a(15) =3658a(16) =6353a(17) =12815a(18) =30844a(19) =61009a(20) =100133a(21) =216534a(22) =514233a(23) =930107a(24) =1686288a(25) =3352737a(26) =8264081a(27) =15163506a(28) =27077825a(29) =53153175