A223653 Number of 3Xn 0..1 arrays with all rows having a nonnegative second derivative, and all and 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

3, 9, 9, 35, 77, 207, 513, 1415, 4009, 12499, 37577, 99863, 300723, 949821, 2565811, 7925175, 23158917, 68824353, 207493163, 617410067, 1841509697, 5611469021, 16589242023, 49212663699, 148570250829, 449163990819, 1326001156759

Offset

1,1

Comments

Row 1 of A223652

Links

R. H. Hardin, Table of n, a(n) for n = 1..38

Example

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

Crossrefs

Sequence in context: A223576 A125824 A203558 * A351929 A238912 A038227

Adjacent sequences: A223650 A223651 A223652 * A223654 A223655 A223656

Keyword

nonn

Author

R. H. Hardin Mar 25 2013

Status

approved