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A252337 Number of (n+2) X (2+2) 0..2 arrays with every 3 X 3 subblock row, column, diagonal and antidiagonal sum not equal to 2 3 or 4. 1
108, 268, 810, 2242, 6030, 16676, 46154, 126892, 349380, 963126, 2653330, 7308822, 20136340, 55476206, 152832896, 421048884, 1159980142, 3195705226, 8804055846, 24254890552, 66821428650, 184090811336, 507164105456, 1397220389014 (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) = a(n-1) + 2*a(n-2) + 6*a(n-3) + 5*a(n-4) + a(n-5) - 2*a(n-6) - 2*a(n-7) -a(n-8) for n>9.

Empirical g.f.: 2*x*(54 + 80*x + 163*x^2 + 124*x^3 + 10*x^4 - 73*x^5 - 68*x^6 - 31*x^7 - 2*x^8) / (1 - x - 2*x^2 - 6*x^3 - 5*x^4 - x^5 + 2*x^6 + 2*x^7 + x^8). - Colin Barker, Dec 03 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 2 of A252343.

Sequence in context: A242867 A255091 A255084 * A204284 A204277 A138669

Adjacent sequences: A252334 A252335 A252336 * A252338 A252339 A252340

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 16 2014

STATUS

approved

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Last modified January 28 09:26 EST 2023. Contains 359851 sequences. (Running on oeis4.)