A223191 Number of nX4 0..2 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

50, 2500, 20016, 1133664, 41164952, 1615611339, 76015542500, 3621550793604

Offset

1,1

Comments

Column 4 of A223195

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A218753 A120998 A267061 * A223807 A223757 A223845

Adjacent sequences: A223188 A223189 A223190 * A223192 A223193 A223194

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved