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A221539
Number of 0..5 arrays of length n with each element differing from at least one neighbor by something other than 1, starting with 0.
1
0, 5, 22, 130, 716, 4018, 22466, 125701, 703193, 3933916, 22007609, 123117952, 688762928, 3853170001, 21555920345, 120591020698, 674626461416, 3774085830607, 21113497129178, 118115957356066, 660780130205831
OFFSET
1,2
COMMENTS
Column 5 of A221542.
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) +3*a(n-2) +9*a(n-4) +6*a(n-5) +3*a(n-6).
Empirical g.f.: x^2*(5 - 3*x + 5*x^2 + 3*x^4) / (1 - 5*x - 3*x^2 - 9*x^4 - 6*x^5 - 3*x^6). - Colin Barker, Oct 18 2017
EXAMPLE
Some solutions for n=6
..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0
..3....3....4....2....3....2....2....5....3....4....5....5....0....4....4....5
..5....2....5....2....3....2....3....0....5....3....1....4....2....2....2....2
..3....0....0....4....2....3....5....5....5....5....1....4....3....4....0....2
..0....1....3....1....4....1....2....4....3....0....2....4....1....1....4....4
..5....3....1....1....4....5....4....0....1....0....4....1....5....4....0....1
CROSSREFS
Sequence in context: A355886 A033462 A111154 * A372139 A028561 A227918
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 19 2013
STATUS
approved