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A223403
Number of nX1 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
4, 16, 36, 150, 558, 2126, 8480, 33639, 131920, 540025, 2122564, 8415455, 33814594, 135946810, 537839881, 2157395672, 8623989781, 34438483139, 137851777060, 551209368188, 2200738232246, 8832752603844, 35249999364267, 140816183400831
OFFSET
1,1
COMMENTS
Column 1 of A223406
LINKS
EXAMPLE
Some solutions for n=3
..0....2....3....3....3....3....2....1....0....2....3....2....2....1....1....0
..1....1....0....1....2....3....0....1....1....1....0....2....1....1....0....0
..2....0....2....3....1....3....0....1....3....3....3....2....1....2....0....0
CROSSREFS
Sequence in context: A318278 A293708 A081456 * A263385 A368215 A130279
KEYWORD
nonn
AUTHOR
R. H. Hardin Mar 20 2013
STATUS
approved