Nim function for Take-a-Prime (or Subtract-a-Prime) Game.

Terms

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