Moebius transform applied thrice to natural numbers.

Terms

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