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A014227 Minimal number of initial pieces needed to reach level n in the Solitaire Army game on a hexagonal lattice (a finite sequence). 3
1, 2, 3, 5, 9, 17, 36, 145 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The hexagonal lattice is the familiar 2-dimensional lattice in which each point has 6 neighbors. This is sometimes called the triangular lattice.

Proved finite in 1991 by John Duncan and Donald Hayes, the last term in the sequence being a(7). - George Bell (gibell(AT)comcast.net), Jul 11 2006

REFERENCES

E. R. Berlekamp, J. H. Conway and R. K. Guy, Winning Ways, Academic Press, NY, 2 vols., 1982, see p. 715.

John Duncan and Donald Hayes, Triangular Solitaire, Journal of Recreational Mathematics, Vol. 23, p. 26-37 (1991)

LINKS

Table of n, a(n) for n=0..7.

G. I. Bell, D. S. Hirschberg, P. Guerrero-Garcia, The minimum size required of a solitaire army.

G. Nebe and N. J. A. Sloane, Home page for hexagonal (or triangular) lattice A2

CROSSREFS

Cf. A014225.

Sequence in context: A179807 A110113 A137155 * A064769 A320641 A047021

Adjacent sequences:  A014224 A014225 A014226 * A014228 A014229 A014230

KEYWORD

nonn,fini,full

AUTHOR

N. J. A. Sloane and E. M. Rains

EXTENSIONS

a(5) and a(6) from George I. Bell (gibell(AT)comcast.net), Feb 02 2007

On Apr 07 2008, Pablo Guerrero-Garcia reports that he together with George I. Bell and Daniel S. Hirschberg have completed the calculation of a(7) and its value is 145. This took nearly 47 hours of computation with a Pentium 4 (AT) 2.80 GHz, 768Mb RAM machine).

STATUS

approved

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Last modified July 15 16:09 EDT 2019. Contains 325049 sequences. (Running on oeis4.)