A223221 Number of nX2 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

4, 16, 25, 121, 361, 1369, 4624, 18769, 68121, 299209, 1096209, 4347225, 17288964, 71961289, 271129156, 1103036944, 4381513249, 17397082404, 69668546704, 278284735729, 1102959947961, 4480296122241, 17736243719364, 70577657904601

Offset

1,1

Comments

Column 2 of A223227

Links

R. H. Hardin, Table of n, a(n) for n = 1..60

Example

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

Crossrefs

Sequence in context: A338406 A351979 A111350 * A210002 A105078 A050707

Adjacent sequences: A223218 A223219 A223220 * A223222 A223223 A223224

Keyword

nonn

Author

R. H. Hardin Mar 18 2013

Status

approved