A250851 Number of (n+1) X (6+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction.

14400, 103293, 614965, 3204951, 15344785, 69543783, 303858745, 1294875471, 5422612945, 22429374423, 91953454825, 374560079391, 1518555885505, 6135323831463, 24724903375705, 99451052025711, 399459752428465

Offset

1,1

Links

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

Formula

Empirical: a(n) = 10*a(n-1) - 35*a(n-2) + 50*a(n-3) - 24*a(n-4); a(n) = (282492*4^n - 462196*3^n + 224994*2^n - 20568)/12.

Empirical g.f.: x*(14400 - 40707*x + 86035*x^2 - 49444*x^3) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)). - Colin Barker, Nov 21 2018

Example

Some solutions for n=2:
..1..1..0..1..1..1..1....3..3..2..3..3..3..3....3..3..2..2..1..1..1
..0..0..0..1..2..3..3....0..0..1..2..2..2..2....0..0..0..0..0..0..0
..0..0..0..1..2..3..3....0..0..1..2..2..3..3....1..1..1..1..3..3..3

Crossrefs

Column 6 of A250853.

Sequence in context: A253266 A190469 A237372 * A226286 A203729 A144649

Adjacent sequences: A250848 A250849 A250850 * A250852 A250853 A250854

Keyword

nonn

Author

R. H. Hardin, Nov 28 2014

Status

approved