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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. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified August 10 12:45 EDT 2022. Contains 356039 sequences. (Running on oeis4.)