A223223 - OEIS

%I #3 Mar 18 2013 20:11:57

%S 11,121,280,3926,26376,251110,2272864,22449494,215688364,2635210346,

%T 26127577834,269923989830,2987354654601,35395852343115

%N Number of nX4 0..1 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 A223227

%e Some solutions for n=3

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 18 2013