login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=1..88.

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 A064631 A298200 * A185585 A072945 A274004

Adjacent sequences:  A072645 A072646 A072647 * A072649 A072650 A072651

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jun 02 2002

STATUS

approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 18 17:51 EDT 2019. Contains 321292 sequences. (Running on oeis4.)