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A221457 Number of 0..6 arrays of length n with each element unequal to at least one neighbor, with new values introduced in 0..6 order. 1
0, 1, 2, 7, 25, 102, 456, 2218, 11605, 64647, 379349, 2320555, 14658240, 94843284, 624544847, 4164947151, 28025750099, 189783308469, 1290899153376, 8808076870934, 60230644078721, 412493027114619, 2827998455493193 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Column 6 of A221459.
LINKS
FORMULA
Empirical: a(n) = 16*a(n-1) - 79*a(n-2) + 70*a(n-3) + 361*a(n-4) - 372*a(n-5) - 964*a(n-6) + 144*a(n-7) + 1116*a(n-8) + 720*a(n-9) + 144*a(n-10).
Empirical g.f.: x^2*(1 - 14*x + 54*x^2 + x^3 - 246*x^4 - 41*x^5 + 411*x^6 + 364*x^7 + 91*x^8) / ((1 - x - x^2)*(1 - 2*x - 2*x^2)*(1 - 3*x - 3*x^2)*(1 - 4*x - 4*x^2)*(1 - 6*x - 6*x^2)). - Colin Barker, Aug 05 2018
EXAMPLE
Some solutions for n=6:
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..1....1....1....1....1....1....1....1....1....1....1....1....1....1....1....1
..2....2....2....2....2....2....1....2....1....2....2....0....2....0....2....2
..1....0....1....3....1....3....2....3....0....1....0....2....2....2....3....1
..3....3....2....1....2....0....2....2....0....0....2....0....0....3....2....2
..1....2....3....2....0....4....3....1....1....1....3....1....1....4....4....1
CROSSREFS
Cf. A221459.
Sequence in context: A150511 A036784 A221456 * A221458 A221453 A097597
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2013
STATUS
approved

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Last modified July 17 05:50 EDT 2024. Contains 374360 sequences. (Running on oeis4.)