A223222 Number of nX3 0..1 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

5, 25, 48, 280, 1036, 4656, 21300, 99324, 447912, 2331228, 11037718, 54004060, 266072957, 1384937047, 6366715673, 32524690652, 162457235830, 799368028605, 3994882068793, 19817398849788, 98320465905394, 500432364807953

Offset

1,1

Comments

Column 3 of A223227

Links

R. H. Hardin, Table of n, a(n) for n = 1..23

Example

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

Crossrefs

Sequence in context: A362092 A098947 A364584 * A273789 A147176 A298041

Adjacent sequences: A223219 A223220 A223221 * A223223 A223224 A223225

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved