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A284076 Number of 2Xn 0..1 arrays with no 1 equal to more than three of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements. 1
0, 0, 1, 6, 33, 176, 858, 4000, 18298, 82176, 363027, 1584090, 6844659, 29327056, 124752876, 527398452, 2217568396, 9279837664, 38668567653, 160517532910, 664042452165, 2738524464624, 11261702650622, 46191451640392 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,4
COMMENTS
Row 2 of A284075.
LINKS
FORMULA
Empirical: a(n) = 9*a(n-1) -24*a(n-2) +30*a(n-3) -84*a(n-4) +48*a(n-5) +106*a(n-6) +318*a(n-7) +813*a(n-8) +919*a(n-9) +990*a(n-10) +756*a(n-11) +216*a(n-12).
Empirical g.f.: x^2*(-1 +3*x -3*x^2 +7*x^3 +30*x^4 +32*x^5 +12*x^6)/ (6*x^4+7*x^3+x^2+3*x-1)^3 . - R. J. Mathar, Mar 21 2017
EXAMPLE
Some solutions for n=4
..1..1..1..1. .0..1..1..1. .1..1..1..0. .1..1..1..1. .1..1..1..0
..0..1..1..1. .1..1..1..1. .1..1..1..1. .1..1..1..0. .1..1..1..0
CROSSREFS
Cf. A284075.
Sequence in context: A086091 A081893 A106850 * A094165 A111994 A092851
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 19 2017
STATUS
approved

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Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)