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A253227 Number of (n+1) X (4+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
335, 742, 914, 1498, 2543, 4490, 8216, 15476, 29780, 58148, 114620, 227276, 452276, 901940, 1800908, 3598460, 7193156, 14382116, 28759580, 57514028, 115022420, 230038676, 460070636, 920133980, 1840260068, 3680511620, 7361014076 (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*(335 - 933*x + 219*x^2 + 1261*x^3 - 1245*x^4 + 343*x^5 - 5*x^6 + x^7) / ((1 - x)^3*(1 - 2*x)).

a(n) = 188 + 1755*2^(n-5) + 60*n + 12*n^2 for n>4.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

CROSSREFS

Column 4 of A253231.

Sequence in context: A119760 A046015 A184076 * A105099 A038648 A224533

Adjacent sequences:  A253224 A253225 A253226 * A253228 A253229 A253230

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 29 2014

STATUS

approved

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Last modified July 2 09:32 EDT 2022. Contains 354999 sequences. (Running on oeis4.)