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A072648 a(n) = [log_{Phi}(n*sqrt(5))], where log_{Phi} is logarithm in the base Phi ( = (sqrt(5)+1)/2) and [] stands for the floor function. 2
1, 3, 3, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 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, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
An approximate "inverse" of A000045 (of the Fibonacci numbers).
LINKS
MAPLE
[seq(floor(log[(sqrt(5)+1)/2](n*sqrt(5))), n=1..120)];
PROG
(Scheme function:) (define (A072648 n) (cond ((zero? n) n) (else (floor->exact (/ (log (* n *Sqrt5*)) *LogPhi*)))))
(define *Sqrt5* (sqrt 5))
(define *Phi* (/ (1+ *Sqrt5*) 2))
(define *LogPhi* (log *Phi*))
CROSSREFS
Used to construct A072649.
Sequence in context: A196337 A349784 A298200 * A185585 A072945 A307912
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jun 02 2002
STATUS
approved

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Last modified March 29 11:45 EDT 2024. Contains 371278 sequences. (Running on oeis4.)