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Number of nX2 0..2 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
1

%I #4 Mar 18 2013 05:42:27

%S 9,81,256,2500,19044,149769,1306449,11573604,98962704,945378009,

%T 8103240324,71267107681,649113816976,5922783740329,51729783444964,

%U 469159715409025,4214751562369924,37759790203876225,340491211679997504

%N Number of nX2 0..2 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 2 of A223195

%H R. H. Hardin, <a href="/A223189/b223189.txt">Table of n, a(n) for n = 1..23</a>

%e Some solutions for n=3

%e ..0..2....2..2....2..2....0..2....2..2....2..2....0..2....2..1....0..1....1..0

%e ..0..1....1..1....2..0....0..0....0..0....2..1....0..1....0..0....0..0....1..0

%e ..0..2....1..0....2..0....2..0....1..1....2..0....1..2....1..2....1..1....2..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 18 2013