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A001441 Number of inequivalent Costas arrays of order n under dihedral group. 4
1, 1, 1, 2, 6, 17, 30, 60, 100, 277, 555, 990, 1616, 2168, 2467, 2648, 2294, 1892, 1283, 810, 446, 259, 114, 25, 12, 8, 29, 89, 23 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

Dihedral group of order 8 acts by rotations and reflections of the square.

REFERENCES

James K Beard, Jon C Russo, Keith Erickson, Michael Moneleone and Mike Wright, Combinatoric collaboration on Costas arrays and radar applications, Proceedings of the IEEE 2004 Radar Conference, April26-29 2004, ISBN 0-7803-8234-X, pp. 260-265 (entries for orders 24 and 25).

James K Beard, Jon C Russo, Keith Erickson, Michael Moneleone and Mike Wright,"Costas Array Generation and Search Methodology," to appear in IEEE Transactions on Aerospace and Electronic Engineering. (Order 26)

CRC Handbook of Combinatorial Designs, C. Colbourn and J. Dinitz, Editors, 1996, IV.7: Costas Arrays by Herbert Taylor (IV.7.6, page 259, Table 2.29).

CRC Standard Mathematical Tables and Formulae, 30th ed. 1996, p. 227 (contains errors).

LINKS

Table of n, a(n) for n=1..29.

K. Drakakis, Results of the enumeration of Costas arrays of order 27.

CROSSREFS

Cf. A008404, A001440, A001442, A008403.

Sequence in context: A105146 A024310 A064516 * A204450 A037261 A239234

Adjacent sequences:  A001438 A001439 A001440 * A001442 A001443 A001444

KEYWORD

nonn,hard,more,nice

AUTHOR

N. J. A. Sloane.

EXTENSIONS

a(24)-a(26) from James K Beard (jkbeard(AT)comcast.net), Dec 04 2005

a(27) (from the Drakakis link) sent by John Healy (johnjhealy(AT)gmail.com), Jul 17 2008

a(18) and a(29) (from http://www.costasarrays.org/), Joerg Arndt, Jun 08 2012.

STATUS

approved

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Last modified August 23 13:33 EDT 2014. Contains 245996 sequences.