Nim function for Take-a-Fibonacci-Game (a subtraction game).

Terms

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