A250627 Number of (n+1)X(3+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

585, 2969, 12151, 43185, 134878, 381834, 994281, 2419996, 5560799, 12176364, 25576273, 51841393, 101867368, 194846773, 364006851, 666173582, 1197388373, 2118591655, 3697349343, 6375941481, 10881696630, 18406254608, 30895710373

Offset

1,1

Comments

Column 3 of A250632

Links

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

Formula

Empirical: a(n) = 9*a(n-1) -30*a(n-2) +31*a(n-3) +67*a(n-4) -220*a(n-5) +136*a(n-6) +300*a(n-7) -546*a(n-8) +78*a(n-9) +572*a(n-10) -494*a(n-11) -130*a(n-12) +404*a(n-13) -152*a(n-14) -100*a(n-15) +99*a(n-16) -15*a(n-17) -14*a(n-18) +7*a(n-19) -a(n-20)

Example

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

Crossrefs

Sequence in context: A252195 A380447 A037995 * A043428 A038486 A024380

Adjacent sequences: A250624 A250625 A250626 * A250628 A250629 A250630

Keyword

nonn

Author

R. H. Hardin, Nov 26 2014

Status

approved