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A123689 Number of points in a square lattice covered by a circle of diameter n if the center of the circle is chosen such that the circle covers the minimum possible number of lattice points. 5
0, 2, 4, 10, 16, 26, 32, 46, 60, 74, 88, 108, 124, 146, 172, 194, 216, 248, 276, 308 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n)<=min(A053411(n),A053414(n),A053415(n)).

LINKS

Table of n, a(n) for n=1..20.

Hugo Pfoertner, Minimal number of points in the square lattice covered by circular disks. Illustrations.

EXAMPLE

a(1)=0: Circle with diameter 1 with center (0.5,0.5) covers no lattice points; a(2)=2: Circle with diameter 2 with center (0,eps) covers 2 lattice points;

a(3)=4: Circle with diameter 3 with center (0.5,0.5) covers 4 lattice points.

CROSSREFS

Cf. A123690, A053411, A053414, A053415, A122224.

The corresponding sequences for the hexagonal lattice and the honeycomb net are A125851 and A127405, respectively.

Sequence in context: A218665 A189558 A111149 * A137928 A144834 A006584

Adjacent sequences:  A123686 A123687 A123688 * A123690 A123691 A123692

KEYWORD

more,nonn

AUTHOR

Hugo Pfoertner, Oct 09 2006

STATUS

approved

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Last modified December 18 23:18 EST 2014. Contains 252175 sequences.