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A258674 Number of (n+2) X (1+2) 0..1 arrays with no 3 x 3 subblock diagonal sum equal to the antidiagonal sum. 1
320, 1600, 8320, 43264, 219648, 1115136, 5744640, 29593600, 151101440, 771506176, 3960635392, 20332478464, 104035123200, 532316160000, 2729194291200, 13992627011584, 71652362682368, 366911879643136, 1880261562204160 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + 32*a(n-3) + 256*a(n-4).
Empirical g.f.: 64*x*(5 + 15*x + 80*x^2 + 256*x^3) / ((1 + 16*x^2)*(1 - 2*x - 16*x^2)). - Colin Barker, Dec 22 2018
EXAMPLE
Some solutions for n=4:
..1..1..1....1..1..0....1..1..1....1..1..0....0..1..0....1..0..1....0..1..1
..0..1..1....1..1..0....1..1..1....1..0..0....0..0..1....1..0..0....1..1..0
..0..0..1....1..1..1....1..1..0....0..1..1....0..1..1....1..0..0....0..1..0
..1..1..1....0..0..1....0..0..1....0..1..0....1..1..0....0..1..0....1..0..1
..1..1..1....1..0..0....0..1..1....0..1..0....1..0..1....0..1..1....1..1..0
..1..0..0....0..1..0....1..0..0....0..1..1....1..1..1....0..1..1....0..0..1
CROSSREFS
Column 1 of A258681.
Sequence in context: A121010 A110289 A258681 * A237326 A055863 A168636
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 07 2015
STATUS
approved

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Last modified June 22 00:43 EDT 2024. Contains 373561 sequences. (Running on oeis4.)