A253454 Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.

19701, 31630, 39463, 52912, 83003, 147332, 285681, 590963, 1287225, 2936843, 7007361, 17462243, 45313545, 121840763, 337369041, 955847123, 2755067865, 8040303083, 23671154721, 70114001603, 208543126185, 622031667803

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>9.

Empirical: a(n) = 529*3^(n-3) + 3431*2^(n-1) + 23248 for n>6.

Empirical g.f.: x*(19701 - 86576*x + 66394*x^2 + 45858*x^3 + 9844*x^4 - 5432*x^5 - 2750*x^6 - 489*x^7 - 54*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)). - Colin Barker, Dec 13 2018

Example

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

Crossrefs

Column 6 of A253456.

Sequence in context: A288885 A253493 A253500 * A237096 A252206 A206508

Adjacent sequences: A253451 A253452 A253453 * A253455 A253456 A253457

Keyword

nonn

Author

R. H. Hardin, Jan 01 2015

Status

approved