A223393 Number of 4 X n 0..2 arrays with all rows having a nonnegative second derivative, and all 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.

31, 961, 5450, 188958, 4182458, 101698908, 2972878486, 84155649292, 2392654352060, 83053389564196

Offset

1,1

Comments

Row 2 of A223391.

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for n=3
..2..0..2....0..0..1....2..1..2....2..2..2....2..0..1....2..2..2....2..1..0
..0..0..0....0..0..0....0..1..2....1..0..0....0..0..1....2..0..0....2..0..1
..2..0..1....1..0..0....2..0..0....2..0..1....1..0..0....0..0..0....0..0..0
..2..1..0....2..1..0....2..2..2....2..0..2....1..1..2....2..0..2....1..0..2

Crossrefs

Cf. A223391.

Sequence in context: A208693 A207563 A207418 * A207390 A207518 A207067

Adjacent sequences: A223390 A223391 A223392 * A223394 A223395 A223396

Keyword

nonn

Author

R. H. Hardin, Mar 19 2013

Status

approved