Farey sequence: Difference between revisions

=={{header|Racket}}== implementation added
m (inserted a missing word in definition.)
(=={{header|Racket}}== implementation added)
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* entry [http://mathworld.wolfram.com/FareySequence.html Farey sequence] on Wolfram Mathworld (TM).
* Wiki [http://en.wikipedia.org/wiki/Farey_sequence Farey sequence] in Wikipedia.
 
=={{header|Racket}}==
 
Once again, racket's ''math/number-theory'' package comes to the rescue!
<lang racket>#lang racket
(require math/number-theory)
(define (display-farey-sequence order show-fractions?)
(define f-s (farey-sequence order))
(printf "-- Farey Sequence for order ~a has ~a fractions~%" order (length f-s))
;; racket will simplify 0/1 and 1/1 to 0 and 1 respectively, so deconstruct into numerator and
;; denomimator (and take the opportunity to insert commas
(when show-fractions?
(displayln
(string-join
(for/list ((f f-s))
(format "~a/~a" (numerator f) (denominator f)))
", "))))
 
; compute and show the Farey sequence for order:
; 1 through 11 (inclusive).
(for ((order (in-range 1 (add1 11)))) (display-farey-sequence order #t))
; compute and display the number of fractions in the Farey sequence for order:
; 100 through 1,000 (inclusive) by hundreds.
(for ((order (in-range 100 (add1 1000) 100))) (display-farey-sequence order #f))</lang>
 
{{out}}
<pre>-- Farey Sequence for order 1 has 2 fractions
0/1, 1/1
-- Farey Sequence for order 2 has 3 fractions
0/1, 1/2, 1/1
-- Farey Sequence for order 3 has 5 fractions
0/1, 1/3, 1/2, 2/3, 1/1
-- Farey Sequence for order 4 has 7 fractions
0/1, 1/4, 1/3, 1/2, 2/3, 3/4, 1/1
-- Farey Sequence for order 5 has 11 fractions
0/1, 1/5, 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 1/1
-- Farey Sequence for order 6 has 13 fractions
0/1, 1/6, 1/5, 1/4, 1/3, 2/5, 1/2, 3/5, 2/3, 3/4, 4/5, 5/6, 1/1
-- Farey Sequence for order 7 has 19 fractions
0/1, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 2/5, 3/7, 1/2, 4/7, 3/5, 2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 1/1
-- Farey Sequence for order 8 has 23 fractions
0/1, 1/8, 1/7, 1/6, 1/5, 1/4, 2/7, 1/3, 3/8, 2/5, 3/7, 1/2, 4/7, 3/5, 5/8, 2/3, 5/7, 3/4, 4/5, 5/6, 6/7, 7/8, 1/1
-- Farey Sequence for order 9 has 29 fractions
0/1, 1/9, 1/8, 1/7, 1/6, 1/5, 2/9, 1/4, 2/7, 1/3, 3/8, 2/5, 3/7, 4/9, 1/2, 5/9, 4/7, 3/5, 5/8, 2/3, 5/7, 3/4, 7/9, 4/5, 5/6, 6/7, 7/8, 8/9, 1/1
-- Farey Sequence for order 10 has 33 fractions
0/1, 1/10, 1/9, 1/8, 1/7, 1/6, 1/5, 2/9, 1/4, 2/7, 3/10, 1/3, 3/8, 2/5, 3/7, 4/9, 1/2, 5/9, 4/7, 3/5, 5/8, 2/3, 7/10, 5/7, 3/4, 7/9, 4/5, 5/6, 6/7, 7/8, 8/9, 9/10, 1/1
-- Farey Sequence for order 11 has 43 fractions
0/1, 1/11, 1/10, 1/9, 1/8, 1/7, 1/6, 2/11, 1/5, 2/9, 1/4, 3/11, 2/7, 3/10, 1/3, 4/11, 3/8, 2/5, 3/7, 4/9, 5/11, 1/2, 6/11, 5/9, 4/7, 3/5, 5/8, 7/11, 2/3, 7/10, 5/7, 8/11, 3/4, 7/9, 4/5, 9/11, 5/6, 6/7, 7/8, 8/9, 9/10, 10/11, 1/1
-- Farey Sequence for order 100 has 3045 fractions
-- Farey Sequence for order 200 has 12233 fractions
-- Farey Sequence for order 300 has 27399 fractions
-- Farey Sequence for order 400 has 48679 fractions
-- Farey Sequence for order 500 has 76117 fractions
-- Farey Sequence for order 600 has 109501 fractions
-- Farey Sequence for order 700 has 149019 fractions
-- Farey Sequence for order 800 has 194751 fractions
-- Farey Sequence for order 900 has 246327 fractions
-- Farey Sequence for order 1000 has 304193 fractions</pre>
 
=={{header|REXX}}==
569

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