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A108852 Number of Fibonacci numbers <= n. 18
1, 3, 4, 5, 5, 6, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
LINKS
Dorin Andrica, Ovidiu Bagdasar, and George Cătălin Tųrcąs, On some new results for the generalised Lucas sequences, An. Şt. Univ. Ovidius Constanţa (Romania, 2021) Vol. 29, No. 1, 17-36.
FORMULA
G.f.: (Sum_{n>=0} x^Fibonacci(n))/(1-x). - Vladeta Jovovic, Nov 27 2005
a(n) = 1+floor(log_phi((sqrt(5)*n+sqrt(5*n^2+4))/2)), n>=0, where phi is the golden ratio. Alternatively, a(n)=1+floor(arcsinh(sqrt(5)*n/2)/log(phi)). Also a(n)=A072649(n)+2. - Hieronymus Fischer, May 02 2007
a(n) = 1+floor(log_phi(sqrt(5)*n+1)), n>=0, where phi is the golden ratio. - Hieronymus Fischer, Jul 02 2007
MATHEMATICA
fibPi[n_] := 1 + Floor[ Log[ GoldenRatio, 1 + n*Sqrt@ 5]]; Array[fibPi, 80, 0] (* Robert G. Wilson v, Aug 03 2014 *)
PROG
(Haskell) fibs :: [Integer]
fibs = 0 : 1 : zipWith (+) fibs (tail fibs)
fibs_to :: Integer -> Integer
fibs_to n = length $ takeWhile (<= n) fibs
CROSSREFS
Sequence in context: A098200 A092405 A130234 * A179413 A119476 A358700
KEYWORD
nonn
AUTHOR
Michael C. Vanier (mvanier(AT)cs.caltech.edu), Nov 27 2005
STATUS
approved

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Last modified February 22 21:30 EST 2024. Contains 370265 sequences. (Running on oeis4.)