a(n) = 3*a(n-2) - a(n-4), a(0)=0, a(1)=1, a(2)=1, a(3)=4. Alternates Fibonacci (A000045) and Lucas (A000032) sequences for even and odd n.
A005013
a(n) = 3*a(n-2) - a(n-4), a(0)=0, a(1)=1, a(2)=1, a(3)=4. Alternates Fibonacci (A000045) and Lucas (A000032) sequences for even and odd n.
Terms
- a(0) =0a(1) =1a(2) =1a(3) =4a(4) =3a(5) =11a(6) =8a(7) =29a(8) =21a(9) =76a(10) =55a(11) =199a(12) =144a(13) =521a(14) =377a(15) =1364a(16) =987a(17) =3571a(18) =2584a(19) =9349a(20) =6765a(21) =24476a(22) =17711a(23) =64079a(24) =46368a(25) =167761a(26) =121393a(27) =439204a(28) =317811a(29) =1149851
External references
- oeis: A005013