a(n) = 8 - (-1)^n.

Terms

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