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A252224 Number of (n+2) X (4+2) 0..2 arrays with every 3 X 3 subblock row and column sum 2 3 or 4 and every diagonal and antidiagonal sum not 2 3 or 4. 1
1442, 7724, 24932, 58334, 160688, 512822, 1619714, 4972874, 15236172, 46914228, 144610766, 445412672, 1371485862, 4223410850, 13006666602, 40055759564, 123355278788, 379883410622, 1169887334864, 3602781631574, 11095111201922 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - a(n-2) + 3*a(n-3) + 3*a(n-4) - a(n-5) - a(n-6) for n>8.
Empirical g.f.: 2*x*(721 + 1699*x + 1601*x^2 - 6532*x^3 - 8440*x^4 - 3717*x^5 + 652*x^6 + 1072*x^7) / ((1 - x + 2*x^2 - x^3)*(1 - 2*x - 3*x^2 - x^3)). - Colin Barker, Dec 02 2018
EXAMPLE
Some solutions for n=4:
..1..1..2..1..1..0....1..0..1..1..1..1....1..1..1..0..2..1....1..1..0..2..0..2
..0..2..0..2..0..2....1..2..0..2..0..2....1..2..0..2..0..2....2..0..2..0..2..1
..2..0..2..0..2..0....2..0..2..0..2..0....2..0..2..0..2..1....0..2..0..2..0..1
..0..2..0..2..0..2....0..2..0..2..0..2....0..2..0..2..0..1....2..0..2..0..2..1
..2..0..2..0..2..0....2..0..2..0..2..0....2..0..2..0..2..1....0..2..0..2..0..2
..0..2..1..1..1..1....1..2..1..1..0..2....1..2..0..2..1..1....1..1..1..0..2..0
CROSSREFS
Column 4 of A252228.
Sequence in context: A362863 A178275 A220651 * A221872 A251842 A105417
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 15 2014
STATUS
approved

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Last modified April 20 21:11 EDT 2024. Contains 371845 sequences. (Running on oeis4.)