a(n) = 28-n.

Terms

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