A250772 Number of (4+1) X (n+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.

72, 130, 216, 350, 572, 962, 1680, 3046, 5700, 10922, 21272, 41870, 82956, 165010, 328992, 656822, 1312340, 2623226, 5244840, 10487902, 20973852, 41945570, 83888816, 167775110, 335547492, 671092042, 1342180920, 2684358446, 5368713260

Offset: 1

Author

R. H. Hardin, Nov 27 2014

Keywords

• nonn

Examples

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

Links

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

Crossrefs

Row 4 of A250769.

Formula

Empirical: a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4); a(n) = 20*2^(n-1) + 4*n^2 + 26*n + 22.

Empirical g.f.: 2*x*(36 - 115*x + 107*x^2 - 32*x^3) / ((1 - x)^3*(1 - 2*x)). - Colin Barker, Nov 19 2018