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 A221593 Number of 0..5 arrays of length n with each element differing from at least one neighbor by 1 or less. 1
 0, 16, 44, 256, 1068, 5082, 22912, 105586, 482204, 2210256, 10115926, 46327024, 212107056, 971225210, 4446995942, 20362020404, 93233503292, 426898240022, 1954682503544, 8950108307086, 40980784959354, 187642965834692 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Column 5 of A221596. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 4*a(n-1) +3*a(n-2) -6*a(n-3) +19*a(n-4) +5*a(n-5) +a(n-6). Empirical g.f.: 2*x^2*(8 - 10*x + 16*x^2 + 4*x^3 + x^4) / (1 - 4*x - 3*x^2 + 6*x^3 - 19*x^4 - 5*x^5 - x^6). - Colin Barker, Oct 19 2017 EXAMPLE Some solutions for n=6 ..2....4....0....0....3....5....2....1....2....4....5....4....2....2....1....3 ..2....3....1....0....3....4....1....0....3....3....5....3....2....1....1....4 ..4....0....5....3....1....2....2....0....2....5....1....2....3....4....2....5 ..4....0....5....4....2....2....2....2....4....4....1....5....1....4....3....5 ..1....4....3....4....3....0....1....3....5....1....1....5....1....4....2....1 ..2....5....2....5....3....1....1....3....4....0....2....5....0....4....3....0 CROSSREFS Sequence in context: A211582 A204032 A192143 * A300962 A051868 A209993 Adjacent sequences:  A221590 A221591 A221592 * A221594 A221595 A221596 KEYWORD nonn AUTHOR R. H. Hardin, Jan 20 2013 STATUS approved

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Last modified December 4 07:28 EST 2021. Contains 349478 sequences. (Running on oeis4.)