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%I #3 Mar 18 2013 05:43:07
%S 50,2500,20016,1133664,41164952,1615611339,76015542500,3621550793604
%N Number of nX4 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 4 of A223195
%e Some solutions for n=3
%e ..1..2..0..2....0..1..1..2....2..1..1..1....2..1..1..2....2..1..0..0
%e ..0..0..0..0....0..0..1..1....0..1..0..1....1..1..0..0....0..0..0..0
%e ..2..2..0..0....2..1..1..1....1..1..1..1....0..1..0..2....2..0..0..0
%K nonn
%O 1,1
%A _R. H. Hardin_ Mar 18 2013