OFFSET
0,2
COMMENTS
A planar additive basis for the square [0,2n]^2 is a set of points with nonnegative integer coordinates such that their pairwise sums cover the square. Self-sums are allowed. In a restricted basis all points are in the lower left quadrant [0,n]^2.
Matches A008574 at least up to a(23)=92.
LINKS
J. Kohonen, V. Koivunen and R. Rajamäki, Planar additive bases for rectangles, arXiv preprint arXiv:1711.08812, [math.NT], 2017.
J. Kohonen, V. Koivunen and R. Rajamäki, Planar additive bases for rectangles, Journal of Integer Sequences, 21 (2018), Article 18.9.8.
EXAMPLE
a(2)=8: the square [0,4]^2 is covered by the pairwise sums of {(0,0),(1,0),(2,0),(0,1),(2,1),(0,2),(1,2),(2,2)}, which has 8 elements.
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Jukka Kohonen, Nov 27 2017
STATUS
approved