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A223495 T(n,k)=Number of (n+2)Xk 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 6
28, 784, 106, 5264, 11236, 466, 164650, 172262, 217156, 1970, 3726450, 20316988, 7974566, 3880900, 7904, 89957891, 1634694162, 4307975642, 332428881, 62473216, 31897, 2474370640, 141426507841, 1422650942236, 802504089833, 12184078320 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

.....28.........784.........5264..........164650..........3726450

....106.......11236.......172262........20316988.......1634694162

....466......217156......7974566......4307975642....1422650942236

...1970.....3880900....332428881....802504089833.1045485381621951

...7904....62473216..12184078320.122450764432500

..31897..1017418609.451243568715

.130224.16958290176

.508551

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..39

EXAMPLE

Some solutions for n=1 k=4

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

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

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

CROSSREFS

Sequence in context: A291997 A171333 A097311 * A209228 A208505 A207878

Adjacent sequences:  A223492 A223493 A223494 * A223496 A223497 A223498

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Mar 20 2013

STATUS

approved

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Last modified November 21 14:18 EST 2019. Contains 329371 sequences. (Running on oeis4.)