A223406 - OEIS

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A223406

T(n,k)=Number of nXk 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

4, 16, 16, 36, 256, 36, 150, 1296, 1296, 150, 558, 22500, 11254, 22500, 558, 2126, 311364, 449810, 449810, 311364, 2126, 8480, 4519876, 13266784, 75789786, 13266784, 4519876, 8480, 33639, 71910400, 417523315, 8686866986, 8686866986

(list; table; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Table starts

......4..........16...........36.............150..............558

.....16.........256.........1296...........22500...........311364

.....36........1296........11254..........449810.........13266784

....150.......22500.......449810........75789786.......8686866986

....558......311364.....13266784......8686866986....3454074121430

...2126.....4519876....417523315...1075376609151.1516052461806611

...8480....71910400..14781272688.158639905687500

..33639..1131582321.521262156765

.131920.17402886400

.540025

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..58

EXAMPLE

Some solutions for n=3 k=4

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

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

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

CROSSREFS

Sequence in context: A341199 A072652 A058970 * A366683 A075382 A203252

Adjacent sequences: A223403 A223404 A223405 * A223407 A223408 A223409

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Mar 20 2013

STATUS

approved