A385159 Place a point on the integer coordinates, up to |n|, along all four axial directions on a Cartesian plane, and then join a circle through every unordered triple of non-collinear points: a(n) is the number of distinct circles created.
1, 18, 99, 280, 633, 1098, 1915, 2928, 4329, 6010, 8331, 10752, 14113, 17778, 21987
Offset: 1
Links
- Scott R. Shannon, Image for n = 2. The 4 x 2 = 8 starting points are shown as white dots.
