

A193555


Numerators of the squared radii of the smallest enclosing circles of n points with integer coordinates and distinct mutual distances, arranged such that the radius of their enclosing circle is minimized. Denominators are given in A193556.


3



1, 5, 5, 5, 5365, 205, 1885, 117925, 3445, 97, 2225, 62530, 284345, 461, 146605
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OFFSET

2,2


COMMENTS

Finding optimal solutions of this problem has been the topic of a round of Al Zimmermann's programming contests from July to October 2009, entitled "Point Packing".
Conjectured next terms are A193555(17)/A193556(17)=19720/121, A193555(18)/A193556(18)=5002/25.


LINKS

Table of n, a(n) for n=2..16.
P. ErdÅ‘s and R. K. Guy, Distinct distances between lattice points, Elemente der Mathematik 25 (1970), 121123.
H. Lefmann and T. Thiele, Point sets with distinct distances, Serie B Informatik, B 9416, 1994.
H. Lefmann and T. Thiele, Point sets with distinct distances, Combinatorica (1995) 15: 379.


CROSSREFS

Cf. A193556 (corresponding denominators), A193839.
Sequence in context: A092519 A198585 A224093 * A161981 A258072 A091284
Adjacent sequences: A193552 A193553 A193554 * A193556 A193557 A193558


KEYWORD

nonn,frac,hard,more


AUTHOR

Hugo Pfoertner, Jul 30 2011


STATUS

approved



