A250734 Number of (5+1) X (n+1) 0..1 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.

99, 230, 600, 1500, 3605, 8514, 19887, 46315, 107565, 249853, 579962, 1346953, 3127694, 7265717, 16877299, 39213972, 91109305, 211714501, 491957956, 1143254321, 2656749170, 6174181500, 14348397804, 33345661179, 77494714919

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 17*a(n-3) + 17*a(n-4) + 12*a(n-5) - 23*a(n-6) + 6*a(n-7) + 3*a(n-8) - a(n-9) for n>12.

Empirical g.f.: x*(99 - 166*x - 320*x^2 + 783*x^3 - 168*x^4 - 804*x^5 + 648*x^6 + 48*x^7 - 119*x^8 - 17*x^9 + 3*x^10 + 3*x^11) / ((1 - x)^3*(1 - x - 6*x^2 + 3*x^3 + 9*x^4 - x^6)). - Colin Barker, Nov 16 2018

Example

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

Crossrefs

Row 5 of A250729.

Sequence in context: A044812 A221373 A260242 * A260279 A250779 A259995

Adjacent sequences: A250731 A250732 A250733 * A250735 A250736 A250737

Keyword

nonn

Author

R. H. Hardin, Nov 27 2014

Status

approved