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A223497 Number of 4Xn 0..3 arrays with all rows having a nonnegative second derivative, and all and columns having a positive second derivative in a quadratic least squares fit, with one and two element arrays taken as having a zero second derivative 0
106, 11236, 172262, 20316988, 1634694162, 141426507841, 14653654917756, 1503865986455078, 147533896792235286 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A223495

LINKS

Table of n, a(n) for n=1..9.

EXAMPLE

Some solutions for n=3

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

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

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

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

CROSSREFS

Sequence in context: A234413 A083963 A166912 * A078281 A253622 A184208

Adjacent sequences:  A223494 A223495 A223496 * A223498 A223499 A223500

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 20 2013

STATUS

approved

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Last modified August 16 05:55 EDT 2022. Contains 356160 sequences. (Running on oeis4.)