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A086676
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Number of n-dimensional 2 X 2 X ... X 2 grid graphs needed to cover an n-dimensional 3 X 3 X ... X 3 torus.
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1
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OFFSET
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1,1
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REFERENCES
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Patric R. J. Östergård and T. Riihonen, A covering problem for tori, Annals of Combinatorics, 7 (2003), 1-7.
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LINKS
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Table of n, a(n) for n=1..9.
D. Brink, The Inverse Football Pool Problem, J. Int. Seq. 14 (2011) # 11.8.8.
Emil Kolev, Covering of {F_3}^n with spheres of maximal radius, Fourteenth International Workshop on Algebraic and Combinatorial Coding Theory, September 7-13, 2014, Svetlogorsk (Kaliningrad region), Russia pp. 198-203.
E. Kolev and T. Baicheva, About the inverse football pool problem for 9 games, Seventh International Workshop on Optimal Codes and Related Topics, September 6-12, 2013, Albena, Bulgaria pp. 125-133.
Patric R. J. Östergård, Home page
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EXAMPLE
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Known bounds for n=10 through 13, from Kolev (2014):
10 102-104
11 153-172
12 230-264
13 345-408
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CROSSREFS
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Sequence in context: A018135 A065435 A301750 * A055804 A267372 A355975
Adjacent sequences: A086673 A086674 A086675 * A086677 A086678 A086679
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane, Jul 28 2003
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EXTENSIONS
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I have added two terms (29 and 44). The ranges for the next terms are [66,68] and [99,104]. David Brink, Jun 03 2009
For a(9) = 68 and further bounds see Kolev and Baicheva. - N. J. A. Sloane, Mar 10 2014
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STATUS
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approved
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