A253344 - OEIS

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A253344

Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock diagonal maximum minus antidiagonal maximum nondecreasing horizontally, vertically and ne-to-sw antidiagonally.

47, 173, 735, 3192, 13917, 60779, 265605, 1161035, 5075841, 22191959, 97027389, 424226867, 1854830841, 8109825551, 35458405365, 155034056747, 677852377137, 2963761021319, 12958396425645, 56657753602595, 247723635757161

(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) = 6*a(n-1) - 5*a(n-2) - 12*a(n-3) + 12*a(n-4) for n>6.

Empirical g.f.: x*(47 - 109*x - 68*x^2 + 211*x^3 - 48*x^4 - 19*x^5) / ((1 - x)*(1 - 2*x)*(1 - 3*x - 6*x^2)). - Colin Barker, Dec 11 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 2 of A253350.

Sequence in context: A139992 A142916 A253351 * A227282 A204610 A158632

Adjacent sequences: A253341 A253342 A253343 * A253345 A253346 A253347

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 30 2014

STATUS

approved