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A253503 Number of (n+2) X (1+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically. 1
132, 260, 428, 636, 884, 1172, 1500, 1868, 2276, 2724, 3212, 3740, 4308, 4916, 5564, 6252, 6980, 7748, 8556, 9404, 10292, 11220, 12188, 13196, 14244, 15332, 16460, 17628, 18836, 20084, 21372, 22700, 24068, 25476, 26924, 28412, 29940, 31508, 33116 (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) = 20*n^2 + 68*n + 44.

Conjectures from Colin Barker, Dec 16 2018: (Start)

G.f.: 4*x*(33 - 34*x + 11*x^2) / (1 - x)^3.

a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>3.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A253510.

Sequence in context: A204649 A224548 A253510 * A195674 A319274 A241754

Adjacent sequences:  A253500 A253501 A253502 * A253504 A253505 A253506

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 02 2015

STATUS

approved

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Last modified November 12 22:04 EST 2019. Contains 329079 sequences. (Running on oeis4.)