A320542 - cp's OEIS frontend

A320542 a(n) is the number of ways to select 3 distinct points forming a triangle of unsigned area = n from a square of grid points with side length n, divided by 4.

%I A320542 #14 Oct 26 2018 12:54:30
%S A320542 0,2,12,33,74,258,294,661,1258,1940,2044,5254,4136,7738,12902,13357,
%T A320542 13142,29540,21214,40816,50388,50012,47680,101662,83684,99690,140638,
%U A320542 158568,126720,282042,167514,253779,318556,302230,386186,579833,350556,478058,629582,765498
%N A320542 a(n) is the number of ways to select 3 distinct points forming a triangle of unsigned area = n from a square of grid points with side length n, divided by 4.
%C A320542 Let s(n) be the number of ways to select 3 different points from a square of grid points with side length n such that they form a triangle with absolute area n, then a(n) = s(n)/4. Permutations of the vertices are considered equivalent.
%Y A320542 Cf. A115004, A320310, A320540, A320544.
%K A320542 nonn
%O A320542 1,2
%A A320542 _Hugo Pfoertner_, Oct 15 2018
%E A320542 a(35)-a(40) from _Giovanni Resta_, Oct 26 2018

cp's OEIS Frontend

A320542 a(n) is the number of ways to select 3 distinct points forming a triangle of unsigned area = n from a square of grid points with side length n, divided by 4.