A250768 Number of (n+1) X (7+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing absolute value of x(i,j)-x(i-1,j) in the j direction.

519, 798, 1158, 1680, 2526, 4020, 6810, 12192, 22758, 43692, 85362, 168504, 334590, 666564, 1330314, 2657616, 5312022, 10620636, 21237666, 42471528, 84939054, 169873908, 339743418, 679482240, 1358959686, 2717914380, 5435823570

Offset

1,1

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3); a(n) = 81*2^(n-1) + 198*n + 240.

Empirical g.f.: 3*x*(173 - 426*x + 187*x^2) / ((1 - x)^2*(1 - 2*x)). - Colin Barker, Nov 19 2018

Example

Some solutions for n=4:
..1..0..1..0..1..1..0..0....0..0..0..0..0..0..0..0....0..1..1..0..0..0..0..0
..1..0..1..0..1..1..1..1....0..0..0..0..0..0..0..0....0..1..1..0..0..0..0..0
..1..0..1..0..1..1..1..1....0..0..0..0..0..0..0..0....0..1..1..1..1..1..1..1
..1..0..1..0..1..1..1..1....0..0..0..0..0..0..0..0....0..1..1..1..1..1..1..1
..1..0..1..0..1..1..1..1....0..0..0..0..1..1..1..1....0..1..1..1..1..1..1..1

Crossrefs

Column 7 of A250769.

Sequence in context: A345587 A345845 A051983 * A043626 A345596 A345855

Adjacent sequences: A250765 A250766 A250767 * A250769 A250770 A250771

Keyword

nonn

Author

R. H. Hardin, Nov 27 2014

Status

approved