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%I #7 Oct 03 2025 21:17:51
%S 989,25929,1328305,55977857,1853983303,63763662879,2163492588961
%N Number of (n+2)X4 0..2 arrays with all rows and columns having a strictly positive second derivative in a quadratic least squares fit.
%C Column 2 of A223157
%e Some solutions for n=1
%e ..1..2..0..2....2..0..1..2....2..2..0..2....1..0..2..2....2..1..1..2
%e ..1..0..0..0....1..0..0..0....1..0..0..0....0..0..0..1....1..0..0..1
%e ..2..1..1..1....2..1..0..0....2..1..2..2....1..2..0..2....2..1..0..2
%K nonn
%O 1,1
%A _R. H. Hardin_, Mar 16 2013