A165164 Smallest k such that no set of n lattice points gives visibility to every point of a square k X k lattice.

4, 6, 24, 133

Offset

1,1

Comments

At least n+1 lattice points must be selected as viewpoints in order to give visibility to all lattice points of a square a(n) X a(n) lattice.

Links

Table of n, a(n) for n=1..4.

Example

For k < 24, given a k X k square lattice, there is at least one way to select a set of 3 or fewer lattice points as viewpoints that, collectively, give visibility to all k^2 lattice points; at k=24, however, no such set of 3 points exists, so a(3)=24.

Crossrefs

Equals minimum k such that A157639(k) > n.

Sequence in context: A343466 A000287 A032087 * A241602 A136591 A277997

Adjacent sequences: A165161 A165162 A165163 * A165165 A165166 A165167

Keyword

hard,nonn

Author

Jon E. Schoenfield, Sep 06 2009

Status

approved