a(n) = 3*a(n-2) - a(n-4), a(0)=2, a(1)=1, a(2)=3, a(3)=2. Alternates Lucas (A000032) and Fibonacci (A000045) sequences for even and odd n.
A005247
a(n) = 3*a(n-2) - a(n-4), a(0)=2, a(1)=1, a(2)=3, a(3)=2. Alternates Lucas (A000032) and Fibonacci (A000045) sequences for even and odd n.
Terms
- a(0) =2a(1) =1a(2) =3a(3) =2a(4) =7a(5) =5a(6) =18a(7) =13a(8) =47a(9) =34a(10) =123a(11) =89a(12) =322a(13) =233a(14) =843a(15) =610a(16) =2207a(17) =1597a(18) =5778a(19) =4181a(20) =15127a(21) =10946a(22) =39603a(23) =28657a(24) =103682a(25) =75025a(26) =271443a(27) =196418a(28) =710647a(29) =514229
External references
- oeis: A005247