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A253454 Number of (n+1) X (6+1) 0..2 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically. 1
19701, 31630, 39463, 52912, 83003, 147332, 285681, 590963, 1287225, 2936843, 7007361, 17462243, 45313545, 121840763, 337369041, 955847123, 2755067865, 8040303083, 23671154721, 70114001603, 208543126185, 622031667803 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
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) + 3431*2^(n-1) + 23248 for n>6.
Empirical g.f.: x*(19701 - 86576*x + 66394*x^2 + 45858*x^3 + 9844*x^4 - 5432*x^5 - 2750*x^6 - 489*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..1..0..1..0..0....0..1..0..2..2..2..2....0..2..1..1..2..0..1
..2..2..2..1..2..1..1....2..2..0..1..0..0..0....0..2..1..1..2..0..1
..1..1..1..0..1..0..0....2..2..0..1..0..0..0....0..2..1..1..2..0..1
..1..1..1..0..1..0..0....2..2..0..1..0..0..1....0..2..1..1..2..0..1
..2..2..2..1..2..1..1....2..2..0..1..0..0..2....0..2..1..1..2..0..2
CROSSREFS
Column 6 of A253456.
Sequence in context: A288885 A253493 A253500 * A237096 A252206 A206508
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 01 2015
STATUS
approved

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Last modified March 2 14:21 EST 2024. Contains 370493 sequences. (Running on oeis4.)