Canonical enumeration of integers: interleaved positive and negative integers with zero prepended.

Terms

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