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%I #11 Dec 12 2015 01:13:34
%S 0,1,4,11,26,46,84,123,194,268,378,478,657,800,1019,1239,1548,1793,
%T 2197,2505,3003,3434,3991,4444,5223,5801,6582,7292,8274,9006,10199,
%U 11034,12330,13398,14744,15912,17705,18906,20586
%N Number of different deltoids (including squares) whose vertices are on an n X n grid.
%C Only convex kites (A189417) are counted, not concave kites (A173502), distinct up to congruence.
%H Nathaniel Johnston, <a href="/A159944/a159944.c.txt">C program for computing terms</a>
%e a(1) = 0, since there is only one point on a 1 X 1 grid.
%e a(2) = 1, since the four points on a 2 X 2 grid build a 1 X 1 square.
%e 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.
%Y Cf. A189417, A173502.
%K nonn
%O 1,3
%A Demacek Ondrej (demacek(AT)gjh.sk), Apr 27 2009
%E Edited by _Ray Chandler_, May 01 2011
%E Corrected and extended by _Nathaniel Johnston_ with help from _Ray Chandler_, May 11 2011
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