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%I #5 Mar 20 2013 04:26:10
%S 4,16,36,150,558,2126,8480,33639,131920,540025,2122564,8415455,
%T 33814594,135946810,537839881,2157395672,8623989781,34438483139,
%U 137851777060,551209368188,2200738232246,8832752603844,35249999364267,140816183400831
%N Number of nX1 0..3 arrays with all rows and columns having a nonnegative second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative
%C Column 1 of A223406
%H R. H. Hardin, <a href="/A223403/b223403.txt">Table of n, a(n) for n = 1..83</a>
%e Some solutions for n=3
%e ..0....2....3....3....3....3....2....1....0....2....3....2....2....1....1....0
%e ..1....1....0....1....2....3....0....1....1....1....0....2....1....1....0....0
%e ..2....0....2....3....1....3....0....1....3....3....3....2....1....2....0....0
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 20 2013