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A283637
Number of 4Xn 0..1 arrays with no 1 equal to more than one of its horizontal, diagonal and antidiagonal neighbors, with the exception of exactly two elements.
1
0, 28, 388, 7742, 61592, 700534, 6345928, 54063960, 463390898, 3745175778, 29932577562, 234328588526, 1803842585678, 13723043109600, 103162171803860, 768173607105144, 5671713327162306, 41562268140668656, 302562753480355030
OFFSET
1,2
COMMENTS
Row 4 of A283634.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) +45*a(n-2) -34*a(n-3) -1527*a(n-4) -4200*a(n-5) +5806*a(n-6) +79440*a(n-7) +256035*a(n-8) +556862*a(n-9) +773985*a(n-10) +907686*a(n-11) +67578*a(n-12) -154770*a(n-13) -3028137*a(n-14) -564902*a(n-15) -5353965*a(n-16) +3950340*a(n-17) -4944390*a(n-18) +9675900*a(n-19) -5062575*a(n-20) +8559650*a(n-21) -5818125*a(n-22) +3153750*a(n-23) -3048625*a(n-24) for n>26
EXAMPLE
Some solutions for n=4
..0..0..1..1. .0..1..0..0. .0..0..0..1. .0..1..1..1. .1..0..1..0
..1..0..0..1. .1..1..0..0. .0..1..0..0. .0..0..0..0. .0..0..1..0
..1..0..0..1. .0..1..0..0. .1..0..0..0. .0..1..1..0. .0..0..0..0
..1..1..0..0. .1..0..0..1. .1..1..0..1. .1..0..1..0. .1..1..1..1
CROSSREFS
Cf. A283634.
Sequence in context: A130608 A331353 A177108 * A126921 A035709 A035476
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 12 2017
STATUS
approved