a(n) = 11-n.

Terms

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