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A223188
Number of n X 1 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.
1
3, 9, 16, 50, 138, 387, 1143, 3402, 9948, 30747, 90018, 266959, 805676, 2433677, 7192342, 21660095, 64921118, 194318785, 583516248, 1749692999, 5235795129, 15779920510, 47191559739, 141322913448, 424521847845, 1275708336588
OFFSET
1,1
COMMENTS
Column 1 of A223195.
LINKS
EXAMPLE
All solutions for n=3
..1....1....2....0....2....1....2....0....2....2....0....1....2....0....2....1
..1....0....0....0....0....0....2....0....1....0....1....0....1....0....1....1
..2....1....2....1....1....0....2....2....0....0....2....2....1....0....2....1
CROSSREFS
Cf. A223195.
Sequence in context: A058538 A197531 A117108 * A145796 A056403 A181349
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 18 2013
STATUS
approved