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A253505 Number of (n+2) X (3+2) 0..1 arrays with every 2 X 2 and 3 X 3 subblock diagonal maximum minus antidiagonal minimum nondecreasing horizontally and vertically. 1
428, 784, 1332, 2088, 3052, 4248, 5692, 7404, 9404, 11712, 14348, 17332, 20684, 24424, 28572, 33148, 38172, 43664, 49644, 56132, 63148, 70712, 78844, 87564, 96892, 106848, 117452, 128724, 140684, 153352, 166748, 180892, 195804, 211504, 228012 (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) = (10/3)*n^3 + 64*n^2 + (566/3)*n + 92 for n>4.

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

G.f.: 4*x*(107 - 232*x + 191*x^2 - 62*x^3 - 4*x^4 + 6*x^5 - 2*x^6 + x^7) / (1 - x)^4.

a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) for n>8.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 3 of A253510.

Sequence in context: A236383 A224668 A030467 * A173798 A233812 A231047

Adjacent sequences:  A253502 A253503 A253504 * A253506 A253507 A253508

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 02 2015

STATUS

approved

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Last modified November 18 22:50 EST 2019. Contains 329305 sequences. (Running on oeis4.)