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A084828 Maximum number of spheres of radius one that can be packed in a sphere of radius n. 5
1, 2, 13, 32, 68 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

a(4) and a(5) are experimental values. Although A121346(5) claims a lower bound of a(5)=68, it is conjectured from extensive numerical search that this value is unachievable and therefore a(5)=67.

The conjecture a(5)=67 was proved wrong by Yu Liang, who found an arrangement of 68 spheres of radius 1 fitting into a sphere of radius 5.

LINKS

Dave Boll, Optimal Packing of Circles and Spheres

Hugo Pfoertner, Numerical results for best packing of spheres in sphere.

Hugo Pfoertner, Densest Packing of Spheres in a Sphere. Java visualization.

Yu Liang, Coordinates of sphere centers of 68 spheres of radius 0.20000222, fitting into a container of radius 1. Private communication, Aug 22, 2011

CROSSREFS

Cf. A121346 Conjectured lower bounds. A084827, A084829, A084825.

Sequence in context: A106959 A177455 A185950 * A100512 A051474 A062708

Adjacent sequences:  A084825 A084826 A084827 * A084829 A084830 A084831

KEYWORD

hard,more,nonn

AUTHOR

Hugo Pfoertner (hugo(AT)pfoertner.org), Jun 12 2003

EXTENSIONS

Comment and links edited, a(5) from Hugo Pfoertner (hugo(AT)pfoertner.org), Jun 23 2011

a(5) corrected, based on private communication from Yu Liang, by Hugo Pfoertner (hugo(AT)pfoertner.org), Aug 24 2011

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Last modified February 15 21:56 EST 2012. Contains 205860 sequences.