a(n) = 3*a(n-2) for n > 2; a(1) = 5, a(2) = 3.

Terms

a(0) =5a(1) =3a(2) =15a(3) =9a(4) =45a(5) =27a(6) =135a(7) =81a(8) =405a(9) =243a(10) =1215a(11) =729a(12) =3645a(13) =2187a(14) =10935a(15) =6561a(16) =32805a(17) =19683a(18) =98415a(19) =59049a(20) =295245a(21) =177147a(22) =885735a(23) =531441a(24) =2657205a(25) =1594323a(26) =7971615a(27) =4782969a(28) =23914845a(29) =14348907