%I #15 Apr 28 2023 20:25:22
%S 0,0,3,6,18,39,81,141,237,369,561,801,1119,1521,2043,2667,3429,4329,
%T 5415,6675,8163,9879,11877,14127,16695,19593,22881,26523,30591,35085,
%U 40089,45591,51681,58359,65715,73701,82389,91791,102015,113007,124875
%N Number of distinct lines passing through exactly two points in a triangular grid of side n.
%F a(n) = A244504(n) - A234248(n). - _Andrew Howroyd_, Apr 03 2023
%Y Cf. A234248, A244504 (lines which contain 2 or more points), A050534 (total number of pairs of points). Both are upper bounds.
%K nonn
%O 0,3
%A _Caleb Stanford_, Apr 03 2023