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A003075 Minimal number of comparisons needed for n-element sorting network.
(Formerly M2446)
3
0, 1, 3, 5, 9, 12, 16, 19, 25, 29, 35, 39, 45, 51, 56, 60 (list; graph; refs; listen; history; internal format)
OFFSET

1,3

COMMENTS

a(13) <= 45 mentioned in Knuth, Sorting and Searching, Vol. 2. a(9) determined in 1991. - Ed Pegg Jr (ed(AT)mathpuzzle.com), Dec 05 2001

REFERENCES

R. W. Floyd and D. E. Knuth, The Bose-Nelson sorting problem, pp. 163-172 of J. N. Srivastava, ed., A Survey of Combinatorial Theory, North-Holland, 1973.

H. Jullie, Lecture Notes in Comp. Sci. 929 (1995), 246-260.

D. E. Knuth, Art of Computer Programming, Vol. 3, Sect. 5.3.4, Eq. (11).

I. Parberry, "A Computer Assisted Optimal Depth Lower Bound for Nine-Input Sorting Networks", Mathematical Systems Theory, Vol. 24, pp. 101-116, 1991.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Ed Pegg Jr., Illustration of initial terms

J. H. Smith, Nine-Input Sorting Networks

Index entries for sequences related to sorting

CROSSREFS

A006282 is an upper bound. Cf. A036604.

Sequence in context: A020946 A091785 A191403 * A061562 A006282 A086845

Adjacent sequences:  A003072 A003073 A003074 * A003076 A003077 A003078

KEYWORD

hard,nonn,nice

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

EXTENSIONS

Terms are exact for n<=9, otherwise the best known (according to Knuth).

Updates from Ed Pegg Jr (ed(AT)mathpuzzle.com), Dec 05 2001

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Last modified February 17 06:27 EST 2012. Contains 205998 sequences.