A223403 Number of nX1 0..3 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, 36, 150, 558, 2126, 8480, 33639, 131920, 540025, 2122564, 8415455, 33814594, 135946810, 537839881, 2157395672, 8623989781, 34438483139, 137851777060, 551209368188, 2200738232246, 8832752603844, 35249999364267, 140816183400831

Offset

1,1

Comments

Column 1 of A223406

Links

R. H. Hardin, Table of n, a(n) for n = 1..83

Example

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

Crossrefs

Sequence in context: A318278 A293708 A081456 * A263385 A368215 A130279

Adjacent sequences: A223400 A223401 A223402 * A223404 A223405 A223406

Keyword

nonn

Author

R. H. Hardin Mar 20 2013

Status

approved