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A223654 Number of 4Xn 0..1 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
5, 25, 43, 229, 799, 3237, 16975, 58813, 262975, 1273157, 6142655, 26877117, 132748947, 716258257, 3072240791, 15826485913, 73962438259, 366204124645, 1830090585655, 8942164068501, 44436414147403, 225094702418657 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 2 of A223652

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

Some solutions for n=3

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

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

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

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

CROSSREFS

Sequence in context: A294256 A056872 A029490 * A098947 A223222 A273789

Adjacent sequences:  A223651 A223652 A223653 * A223655 A223656 A223657

KEYWORD

nonn

AUTHOR

R. H. Hardin Mar 25 2013

STATUS

approved

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Last modified October 17 13:07 EDT 2021. Contains 348048 sequences. (Running on oeis4.)