A223656 Number of 6Xn 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

27, 729, 1973, 78213, 1044311, 22982345, 502081983, 9622736121, 218268103915, 6831466723781, 157202982490683, 3596007897529929

Offset

1,1

Comments

Row 4 of A223652

Links

Table of n, a(n) for n=1..12.

Example

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

Crossrefs

Sequence in context: A218729 A171332 A097781 * A073537 A016947 A223790

Adjacent sequences: A223653 A223654 A223655 * A223657 A223658 A223659

Keyword

nonn

Author

R. H. Hardin Mar 25 2013

Status

approved