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 A221685 Number of 0..n arrays of length 6 with each element differing from at least one neighbor by 1 or less, starting with 0. 1
 32, 113, 241, 418, 636, 891, 1182, 1509, 1872, 2271, 2706, 3177, 3684, 4227, 4806, 5421, 6072, 6759, 7482, 8241, 9036, 9867, 10734, 11637, 12576, 13551, 14562, 15609, 16692, 17811, 18966, 20157, 21384, 22647, 23946, 25281, 26652, 28059, 29502, 30981 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 6 of A221683. LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 18*n^2 + 57*n - 99 for n>4. Conjectures from Colin Barker, Aug 10 2018: (Start) G.f.: x*(32 + 17*x - 2*x^2 + 2*x^3 - 8*x^4 - 4*x^5 - x^6) / (1 - x)^3. a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n>7. (End) EXAMPLE Some solutions for n=6: ..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0 ..1....0....0....1....1....0....1....0....1....0....0....0....1....0....1....0 ..3....0....2....5....0....6....3....0....0....1....5....6....0....1....4....4 ..4....0....1....5....3....5....4....1....5....5....4....6....0....3....4....5 ..3....0....4....2....2....1....2....2....4....4....3....1....2....2....0....2 ..2....1....4....2....2....2....3....1....4....3....2....1....3....3....0....3 CROSSREFS Cf. A221683. Sequence in context: A203728 A044283 A044664 * A203721 A231527 A298201 Adjacent sequences:  A221682 A221683 A221684 * A221686 A221687 A221688 KEYWORD nonn AUTHOR R. H. Hardin, Jan 22 2013 STATUS approved

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Last modified June 26 09:52 EDT 2022. Contains 354879 sequences. (Running on oeis4.)