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A223222 Number of nX3 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 1
5, 25, 48, 280, 1036, 4656, 21300, 99324, 447912, 2331228, 11037718, 54004060, 266072957, 1384937047, 6366715673, 32524690652, 162457235830, 799368028605, 3994882068793, 19817398849788, 98320465905394, 500432364807953 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A223227

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..23

EXAMPLE

Some solutions for n=3

..1..0..0....1..1..1....1..0..0....1..0..1....1..0..1....1..0..1....0..0..1

..1..0..0....1..0..1....0..0..0....0..0..0....0..0..0....1..0..0....0..0..1

..1..0..1....1..0..1....1..0..0....1..0..0....0..0..0....1..0..0....1..1..1

CROSSREFS

Sequence in context: A029490 A223654 A098947 * A273789 A147176 A298041

Adjacent sequences:  A223219 A223220 A223221 * A223223 A223224 A223225

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 18 2013

STATUS

approved

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Last modified October 27 20:04 EDT 2021. Contains 348289 sequences. (Running on oeis4.)