A253229 Number of (n+1) X (6+1) 0..1 arrays with every 2 X 2 subblock diagonal minimum minus antidiagonal minimum nondecreasing horizontally and diagonal maximum minus antidiagonal maximum nondecreasing vertically.

2470, 4158, 3241, 4490, 6414, 9630, 15363, 26064, 46635, 86880, 166407, 324432, 639387, 1268136, 2524407, 5035656, 10056795, 20097648, 40177863, 80336736, 160652859, 321283416, 642542775, 1285059672, 2570091579, 5140153440

Offset

1,1

Links

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

Formula

Empirical: a(n) = 5*a(n-1) - 9*a(n-2) + 7*a(n-3) - 2*a(n-4) for n>8.

Conjectures from Colin Barker, Dec 10 2018: (Start)

G.f.: x*(2470 - 8192*x + 4681*x^2 + 8417*x^3 - 11033*x^4 + 3599*x^5 - 9*x^6 + x^7) / ((1 - x)^3*(1 - 2*x)).

a(n) = 1128 + 2451*2^(n-5) + 402*n + 33*n^2 for n>4.

(End)

Example

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

Crossrefs

Column 6 of A253231.

Sequence in context: A252113 A102689 A082253 * A253348 A253355 A204614

Adjacent sequences: A253226 A253227 A253228 * A253230 A253231 A253232

Keyword

nonn

Author

R. H. Hardin, Dec 29 2014

Status

approved