A200528 Number of n X 2 0..2 arrays with every row and column running average nondecreasing rightwards and downwards.

6, 20, 57, 146, 354, 825, 1873, 4169, 9144, 19825, 42590, 90815, 192457, 405760, 851740, 1781227, 3713015, 7718092, 16003641, 33111477, 68374642, 140947848, 290098848, 596244613, 1223916576, 2509450811, 5139839214, 10517282966

Offset: 1

Author

R. H. Hardin, Nov 18 2011

Keywords

• nonn

Comments

Column 2 of A200534.

Examples

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

Links

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

Crossrefs

Cf. A200534.

Formula

Empirical: a(n) = 7*a(n-1) -16*a(n-2) +6*a(n-3) +27*a(n-4) -33*a(n-5) -3*a(n-6) +24*a(n-7) -11*a(n-8) -4*a(n-9) +4*a(n-10).

Empirical g.f.: x*(6 - 22*x + 13*x^2 + 31*x^3 - 38*x^4 - x^5 + 25*x^6 - 11*x^7 - 4*x^8 + 4*x^9) / ((1 - x)*(1 + x)*(1 - 2*x)^2*(1 - x - x^2)*(1 - 2*x + x^3 - x^4)). - Colin Barker, May 21 2018