

A086676


Number of ndimensional 2 X 2 X ... X 2 grid graphs needed to cover an ndimensional 3 X 3 X ... X 3 torus.


1




OFFSET

1,1


REFERENCES

Patric R. J. Östergård and T. Riihonen, A covering problem for tori, Annals of Combinatorics, 7 (2003), 17.


LINKS

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 713, 2014, Svetlogorsk (Kaliningrad region), Russia pp. 198203.
E. Kolev and T. Baicheva, About the inverse football pool problem for 9 games, Seventh International Workshop on Optimal Codes and Related Topics, September 612, 2013, Albena, Bulgaria pp. 125133.
Patric R. J. Östergård, Home page


EXAMPLE

Known bounds for n=10 through 13, from Kolev (2014):
10 102104
11 153172
12 230264
13 345408


CROSSREFS

Sequence in context: A018135 A065435 A301750 * A055804 A267372 A355975
Adjacent sequences: A086673 A086674 A086675 * A086677 A086678 A086679


KEYWORD

nonn


AUTHOR

N. J. A. Sloane, Jul 28 2003


EXTENSIONS

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


STATUS

approved



