A159944 Number of different deltoids (including squares) whose vertices are on an n X n grid.
0, 1, 4, 11, 26, 46, 84, 123, 194, 268, 378, 478, 657, 800, 1019, 1239, 1548, 1793, 2197, 2505, 3003, 3434, 3991, 4444, 5223, 5801, 6582, 7292, 8274, 9006, 10199, 11034, 12330, 13398, 14744, 15912, 17705, 18906, 20586
Offset: 1
Keywords
Examples
a(1) = 0, since there is only one point on a 1 X 1 grid. a(2) = 1, since the four points on a 2 X 2 grid build a 1 X 1 square. a(3) = 4 since there are 3 sizes of squares on a 3 X 3 grid -- 1 X 1, 2 X 2, sqrt(2) X sqrt(2) -- and a single nonsquare deltoid.
Links
- Nathaniel Johnston, C program for computing terms
Extensions
Edited by Ray Chandler, May 01 2011
Corrected and extended by Nathaniel Johnston with help from Ray Chandler, May 11 2011
Comments