a(n) = mu(n) + 1, where mu is the Moebius function.

Terms

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