A250626 Number of (n+1)X(2+1) 0..2 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

154, 654, 2347, 7342, 20743, 53847, 130848, 300960, 662000, 1402495, 2879592, 5756842, 11251304, 21566446, 40653388, 75532791, 138589211, 251524429, 452156139, 806055771, 1426424994, 2507933115, 4384197749, 7625189535

Offset

1,1

Comments

Column 2 of A250632

Links

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

Formula

Empirical: a(n) = 6*a(n-1) -10*a(n-2) -8*a(n-3) +40*a(n-4) -22*a(n-5) -47*a(n-6) +56*a(n-7) +15*a(n-8) -46*a(n-9) +8*a(n-10) +16*a(n-11) -6*a(n-12) -2*a(n-13) +a(n-14)

Example

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

Crossrefs

Sequence in context: A261377 A256024 A239564 * A235107 A235100 A230804

Adjacent sequences: A250623 A250624 A250625 * A250627 A250628 A250629

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved