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A089676 Maximum size of a set of points S in {0,1}^d such that every angle determined by three points in S is acute. +0
1
1, 2, 2, 4, 5, 6, 8, 9, 10, 16 (list; graph; listen)
OFFSET

0,2

COMMENT

If k<=m<=n, a(k+2m)>=a(k)a(m), a(k+2m+3n)>=a(k)a(m)a(n). a(n) >= 2*floor[(sqrt(6)/9)(2/sqrt(3))^n], approx 0.544*1.155^n.

REFERENCES

L. Danzer and B. Gruenbaum, Uber zwei Probleme bezuglich konvexer Korper von P. Erdos und von K. L. Klee, Math. Zeitschrift 79 (1962) 95-99.

P. Erdos and Z. Furedi, The greatest angle among n points in the d-dimensional Euclidean space, Annals of Discrete Math. 17 (1983) 275-283.

LINKS

D. Bevan, Sets of Points Determining Only Acute Angles and Some Related Colouring Problems, Electronic J. of Combinatorics, 13(1), 2006, #R12.

EXAMPLE

a(3)=4: {000, 011, 101, 110}

CROSSREFS

Sequence in context: A024683 A071528 A056902 this_sequence A062436 A121269 A056219

Adjacent sequences: A089673 A089674 A089675 this_sequence A089677 A089678 A089679

KEYWORD

nonn

AUTHOR

David Bevan (dbevan(AT)emtex.com), Jan 06 2004

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Last modified August 19 23:53 EDT 2008. Contains 142930 sequences.


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