OFFSET
1,2
COMMENTS
Permutations of the 3 points are not counted separately.
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..100
EXAMPLE
a(1) = 0 because no triangle of area 1 can be formed from the corner points of the [0,1]X[0,1] square.
a(2) = 4 because 3 triangles of area 1 can be formed by connecting the end points of any of the 8 segments of length 1 on the periphery of the [0,2]X[0,2] square to any of the 3 vertices on the opposite side of the grid square, making 8*3 = 24 triangles. Additionally, 4 triangles of the type (0,0),(0,2),(1,2) and another 4 triangles of the type (2,1),(0,1),(1,0) can be selected. 24 + 4 + 4 = 32, a(2) = 32/8 = 4.
CROSSREFS
KEYWORD
nonn
AUTHOR
Hugo Pfoertner, Oct 21 2018
EXTENSIONS
a(27)-a(40) from Giovanni Resta, Oct 26 2018
STATUS
approved