A320310 (1/4) * number of ways to select 3 distinct points forming a triangle of unsigned area = n/2 from a square of grid points with side length n.

1, 8, 23, 82, 114, 416, 373, 1149, 1351, 2598, 2113, 7158, 4094, 9344, 11528, 18243, 11882, 33006, 18603, 48760, 42102, 54312, 40061, 121728, 68115, 105204, 112546, 178322, 101798, 284980, 133229, 300367, 247900, 305062, 295972, 625544, 271864, 475004, 479658, 847208

Offset: 1

Author

Hugo Pfoertner, Oct 23 2018

Keywords

• nonn

Comments

Permutations of the 3 points are not counted separately.

Links

• Giovanni Resta, Table of n, a(n) for n = 1..100

Crossrefs

Cf. A115004, A320540, A320542, A320544.

Extensions

a(35)-a(40) from Giovanni Resta, Oct 26 2018