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

Terms

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