A253493 Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

19701, 20975, 25715, 37469, 61955, 113573, 224747, 470909, 1034675, 2376533, 5703227, 14285549, 37236995, 100500293, 279108107, 792567389, 2288216915, 6685708853, 19699271387, 58382132429, 173715062435, 518282546213

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) for n>6.

Empirical: a(n) = 49*3^(n-1) + 2730*2^(n-1) + 14306 for n>3.

Conjectures from Colin Barker, Dec 16 2018: (Start)

G.f.: x*(19701 - 97231*x + 116576*x^2 - 4302*x^3 - 5844*x^4 - 288*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x)).

a(n) = 14306 + 1365*2^n + 49*3^(n-1) for n>3.

(End)

Example

Some solutions for n=4:
..0..1..0..1..2..0..0....0..1..0..0..2..1..1....0..2..2..2..1..1..1
..2..1..0..1..2..0..0....2..2..0..0..2..1..1....1..2..2..2..1..1..1
..2..1..0..1..2..0..0....2..2..0..0..2..1..1....1..2..2..2..1..1..1
..2..1..0..1..2..0..0....2..2..0..0..2..1..1....0..1..1..1..0..0..0
..2..1..0..1..2..0..1....2..2..0..0..2..1..2....0..1..1..1..0..0..2

Crossrefs

Column 6 of A253495.

Sequence in context: A321813 A081866 A288885 * A253500 A253454 A237096

Adjacent sequences: A253490 A253491 A253492 * A253494 A253495 A253496

Keyword

nonn

Author

R. H. Hardin, Jan 02 2015

Status

approved