a(n) = 22-n.

Terms

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