A223392 Number of 3Xn 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.

11, 121, 388, 4794, 40416, 375698, 4128762, 41424210, 415135608, 4912230456, 49929186692, 536801738054, 5986390459865, 67884672672695

Offset

1,1

Comments

Row 1 of A223391

Links

Table of n, a(n) for n=1..14.

Example

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

Crossrefs

Sequence in context: A216131 A338784 A396541 * A262468 A221964 A223640

Adjacent sequences: A223389 A223390 A223391 * A223393 A223394 A223395

Keyword

nonn

Author

R. H. Hardin, Mar 19 2013

Status

approved