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 A251889 Number of (n+2) X (3+2) 0..3 arrays with every 3 X 3 subblock row and column sum not 2 3 6 or 7 and every diagonal and antidiagonal sum 2 3 6 or 7. 1
 1280, 602, 556, 778, 1260, 1636, 2478, 3940, 5958, 9178, 14534, 22666, 35250, 55690, 88338, 138082, 217874, 348706, 546498, 861730, 1385538, 2174338, 3427394, 5523586, 8674050, 13670530, 22057218, 34649602, 54604034, 88154626, 138505218 (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) + 6*a(n-3) - 6*a(n-4) - 8*a(n-6) + 8*a(n-7) for n>12. Empirical g.f.: 2*x*(640 - 339*x - 23*x^2 - 3729*x^3 + 2275*x^4 + 326*x^5 + 4875*x^6 - 3427*x^7 - 303*x^8 - 28*x^9 + 220*x^10 - 484*x^11) / ((1 - x)*(1 - 2*x^3)*(1 - 4*x^3)). - Colin Barker, Nov 30 2018 EXAMPLE Some solutions for n=4: ..0..0..1..0..0....2..3..0..1..0....3..3..2..3..0....2..1..1..2..1 ..0..0..1..0..0....1..0..0..1..0....3..3..2..3..3....1..0..0..1..0 ..1..1..3..1..1....2..1..1..3..1....2..2..0..2..2....1..0..0..1..0 ..0..0..1..0..0....1..0..0..1..0....3..3..2..3..3....2..1..1..3..1 ..3..0..1..0..3....1..0..0..1..0....3..3..2..3..0....1..0..0..1..3 ..1..1..2..1..1....3..1..1..2..1....2..2..0..2..2....1..0..0..1..0 CROSSREFS Column 3 of A251894. Sequence in context: A031798 A293923 A251890 * A251886 A234137 A160233 Adjacent sequences: A251886 A251887 A251888 * A251890 A251891 A251892 KEYWORD nonn AUTHOR R. H. Hardin, Dec 10 2014 STATUS approved

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Last modified September 13 18:22 EDT 2024. Contains 375910 sequences. (Running on oeis4.)