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A253455 Number of (n+1) X (7+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically. 1
48293, 74324, 89556, 114717, 170184, 285681, 526430, 1036512, 2142374, 4611192, 10320110, 24051792, 58456694, 148091112, 389833790, 1060740672, 2964819014, 8459769432, 24510051470, 71791759152, 211898605334, 628742590152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..147

FORMULA

Empirical: a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) for n>9.

Empirical: a(n) = 529*3^(n-3) + 6631*2^(n-1) + 59197 for n>6.

Empirical g.f.: x*(48293 - 215434*x + 174835*x^2 + 105187*x^3 + 21054*x^4 - 10872*x^5 - 3934*x^6 - 681*x^7 - 54*x^8) / ((1 - x)*(1 - 2*x)*(1 - 3*x)). - Colin Barker, Dec 13 2018

EXAMPLE

Some solutions for n=4:

..0..1..2..2..1..1..1..1....0..1..1..2..2..1..2..2....0..2..1..0..1..1..2..0

..1..1..1..1..0..0..0..0....1..1..0..1..1..0..1..1....1..2..1..0..1..1..2..0

..1..1..1..1..0..0..0..0....2..2..1..2..2..1..2..2....1..2..1..0..1..1..2..0

..1..1..1..1..0..0..0..0....1..1..0..1..1..0..1..1....1..2..1..0..1..1..2..1

..2..2..2..2..1..1..1..2....1..1..0..1..1..0..1..1....1..2..1..0..1..1..2..2

CROSSREFS

Column 7 of A253456.

Sequence in context: A227701 A253494 A253501 * A233890 A031867 A151839

Adjacent sequences:  A253452 A253453 A253454 * A253456 A253457 A253458

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 01 2015

STATUS

approved

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Last modified October 15 12:31 EDT 2019. Contains 328026 sequences. (Running on oeis4.)