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%I #10 Oct 22 2018 14:28:46
%S 0,3,16,8,35,72,15,62,125,212,24,95,190,319,476,35,136,269,450,669,
%T 936,48,183,360,601,892,1245,1652,63,238,467,776,1149,1602,2123,2724,
%U 80,299,584,967,1430,1991,2636,3379,4188,99,368,717,1186,1751,2436,3223,4130,5117,6248
%N (1/2) * number of ways to select 3 distinct points forming a triangle of unsigned area = 1 from a rectangle of grid points with side lengths j and k, written as triangle T(j,k), j<=k.
%e The triangle begins:
%e 0
%e 3 16
%e 8 35 72
%e 15 62 125 212
%e 24 95 190 319 476
%e 35 136 269 450 669 936
%e .
%e a(2) = T(1,2) = 3 = 6/2 because the following 6 triangles of area 1 can be made by selecting 3 grid points from the [0,1]X[0,2] rectangle:
%e (0,0) (0,2) (1,0),
%e (0,0) (0,2) (1,1),
%e (0,0) (0,2) (1,2),
%e (0,0) (1,0) (1,2),
%e (0,1) (1,0) (1,2),
%e (0,2) (1,0) (1,2).
%Y Cf. A005563, A320539, A320541, A320544.
%K nonn,tabl
%O 1,2
%A _Hugo Pfoertner_, Oct 16 2018
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