a(n) = 10*Fibonacci(n) + (-1)^n.

Terms

a(0) =1a(1) =9a(2) =11a(3) =19a(4) =31a(5) =49a(6) =81a(7) =129a(8) =211a(9) =339a(10) =551a(11) =889a(12) =1441a(13) =2329a(14) =3771a(15) =6099a(16) =9871a(17) =15969a(18) =25841a(19) =41809a(20) =67651a(21) =109459a(22) =177111a(23) =286569a(24) =463681a(25) =750249a(26) =1213931a(27) =1964179a(28) =3178111a(29) =5142289