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A223405 Number of nX3 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 0
36, 1296, 11254, 449810, 13266784, 417523315, 14781272688, 521262156765, 17822960179390, 683066414115964, 23438466168324477 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A223406

LINKS

Table of n, a(n) for n=1..11.

EXAMPLE

Some solutions for n=3

..3..1..0....2..2..2....1..1..2....1..0..2....1..0..1....3..3..3....3..2..2

..1..0..0....1..1..1....2..1..2....1..0..2....0..0..0....1..0..2....2..0..1

..3..2..1....0..1..2....3..1..3....3..0..2....1..2..3....3..1..3....3..2..3

CROSSREFS

Sequence in context: A218738 A158700 A144128 * A224267 A223924 A224352

Adjacent sequences:  A223402 A223403 A223404 * A223406 A223407 A223408

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 20 2013

STATUS

approved

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Last modified June 26 03:22 EDT 2022. Contains 354871 sequences. (Running on oeis4.)