login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A115339 a(2n-1)=F(n+1), a(2n)=L(n), where F(n) and L(n) are the Fibonacci and the Lucas sequences. 4
1, 1, 2, 3, 3, 4, 5, 7, 8, 11, 13, 18, 21, 29, 34, 47, 55, 76, 89, 123, 144, 199, 233, 322, 377, 521, 610, 843, 987, 1364, 1597, 2207, 2584, 3571, 4181, 5778, 6765, 9349, 10946, 15127, 17711, 24476, 28657, 39603, 46368, 64079, 75025, 103682, 121393, 167761 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Alternate Fibonacci and Lucas sequence respecting their natural order.
See A116470 for an essentially identical sequence.
LINKS
Eric Weisstein's World of Mathematics, Fibonacci Number
Eric Weisstein's World of Mathematics, Lucas Number.
FORMULA
a(n+2) = a(n) + a(n-2).
G.f.: x*( -1-x-x^2-2*x^3 ) / ( -1+x^2+x^4 ). - R. J. Mathar, Mar 08 2011
MATHEMATICA
f[n_] := If[OddQ@n, Fibonacci[(n + 3)/2], Fibonacci[n/2 - 1] + Fibonacci[n/2 + 1]]; Array[f, 50] (* Robert G. Wilson v *)
PROG
(Haskell)
a115339 n = a115339_list !! (n-1)
a115339_list = [1, 1, 2, 3] ++
zipWith (+) a115339_list (drop 2 a115339_list)
-- Reinhard Zumkeller, Aug 03 2013
(PARI) x='x+O('x^50); Vec(x*(-1-x-x^2-2*x^3)/(-1+x^2+x^4)) \\ G. C. Greubel, Apr 27 2017
CROSSREFS
Cf. A000930.
Sequence in context: A343941 A280127 A237977 * A305631 A036019 A018120
KEYWORD
easy,nonn
AUTHOR
Giuseppe Coppoletta, Mar 06 2006
EXTENSIONS
More terms from Robert G. Wilson v, Apr 29 2006
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 22 12:20 EDT 2024. Contains 371900 sequences. (Running on oeis4.)