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A223404 Number of nX2 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 1

%I

%S 16,256,1296,22500,311364,4519876,71910400,1131582321,17402886400,

%T 291627000625,4505277934096,70819882857025,1143426767384836,

%U 18481535149176100,289271737594094161,4654356085564331584

%N Number of nX2 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 2 of A223406

%H R. H. Hardin, <a href="/A223404/b223404.txt">Table of n, a(n) for n = 1..43</a>

%e Some solutions for n=3

%e ..1..1....3..3....2..1....1..3....3..3....3..3....3..1....2..3....3..0....1..1

%e ..0..0....1..3....1..2....1..2....1..0....0..2....2..2....0..1....0..1....0..1

%e ..1..2....1..3....0..3....3..3....0..0....2..3....1..3....1..0....3..2....0..1

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 20 2013

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Last modified July 6 15:57 EDT 2022. Contains 355111 sequences. (Running on oeis4.)