

A125851


Number of points in a hexagonal lattice covered by a circular disk of diameter n if the center of the circle is chosen such that the disk covers the minimum possible number of lattice points.


7



0, 3, 6, 12, 19, 30, 40, 54, 69, 87, 102, 123, 149, 174, 198, 225, 253, 287, 313, 354, 396, 435
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OFFSET

1,2


COMMENTS

a(n)<=min(A053416(n),A053479(n),A053417(n))


LINKS

Table of n, a(n) for n=1..22.
Index entries for sequences related to A2 = hexagonal = triangular lattice
Hugo Pfoertner, Minimal number of points in the hexagonal lattice covered by circular disks. Illustrations.


CROSSREFS

Cf. A053416, A053479, A053417, A125852. The corresponding sequences for the square lattice and the honeycomb net are A123689 and A127405, respectively.
Sequence in context: A101423 A263511 A180622 * A209489 A181962 A226220
Adjacent sequences: A125848 A125849 A125850 * A125852 A125853 A125854


KEYWORD

more,nonn


AUTHOR

Hugo Pfoertner, Jan 07 2007, Feb 11 2007


STATUS

approved



