A253361 - OEIS

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A253361

Number of (n+2) X (2+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum unequal to its neighbors horizontally and vertically.

272, 424, 960, 1536, 3136, 5664, 10496, 20000, 36160, 68672, 125760, 234816, 436032, 807360, 1505344, 2787648, 5189184, 9632576, 17894464, 33259840, 61745728, 114769216, 213107776, 395978560, 735485504, 1366348096, 2538108992

(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-2) - 8*a(n-4) + 8*a(n-6) + 4*a(n-8).

Empirical g.f.: 8*x*(34 + 53*x - 50*x^2 - 73*x^3 + 64*x^4 + 172*x^5 + 40*x^6 + 72*x^7) / (1 - 5*x^2 + 8*x^4 - 8*x^6 - 4*x^8). - Colin Barker, Dec 11 2018

EXAMPLE

Some solutions for n=4:

..0..1..1..1....0..1..0..1....1..1..1..1....1..0..0..1....0..1..0..0

..1..0..1..0....1..0..1..0....1..0..1..1....0..1..0..1....1..0..1..0

..0..1..1..1....0..0..0..1....1..1..0..1....0..0..0..0....0..1..0..0

..1..0..1..0....1..0..1..0....1..1..1..1....0..1..0..1....0..0..1..0

..1..1..1..1....0..0..0..0....0..1..0..1....1..0..0..0....0..1..0..1

..1..0..1..1....1..0..1..0....1..0..1..1....1..1..0..1....0..0..0..0

CROSSREFS

Column 2 of A253367.

Sequence in context: A304892 A316574 A062906 * A133514 A235293 A270302

Adjacent sequences: A253358 A253359 A253360 * A253362 A253363 A253364

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 30 2014

STATUS

approved