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 A269689 Number of length-n 0..7 arrays with no repeated value differing from the previous repeated value by plus or minus one modulo 7+1. 1
 8, 64, 512, 4080, 32416, 256880, 2031072, 16027696, 126262688, 993181680, 7802084704, 61219340720, 479867497248, 3758025752944, 29406845849312, 229946299629360, 1796916741666976, 14034055973604080, 109551619154344032 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS R. H. Hardin, Table of n, a(n) for n = 1..210 FORMULA Empirical: a(n) = 14*a(n-1) - 43*a(n-2) - 42*a(n-3). Conjectures from Colin Barker, Jan 27 2019: (Start) G.f.: 8*x*(1 - 6*x - 5*x^2) / ((1 - 7*x)*(1 - 7*x - 6*x^2)). a(n) = (2^(1-n)*(-73*2^(2+n)*7^n - 7*(7-sqrt(73))^n*(-73+9*sqrt(73)) + 7*(7+sqrt(73))^n*(73+9*sqrt(73)))) / 1533. (End) EXAMPLE Some solutions for n=5: ..1. .0. .0. .1. .5. .5. .6. .7. .6. .4. .1. .1. .7. .0. .2. .0 ..6. .3. .5. .3. .2. .4. .6. .1. .7. .0. .6. .3. .1. .4. .6. .3 ..1. .6. .4. .1. .2. .0. .6. .4. .2. .6. .6. .4. .3. .0. .6. .7 ..0. .6. .4. .3. .5. .1. .5. .4. .6. .1. .5. .1. .4. .1. .6. .5 ..3. .0. .5. .2. .2. .7. .6. .1. .7. .4. .7. .6. .2. .7. .1. .7 CROSSREFS Column 7 of A269690. Sequence in context: A269618 A269582 A269434 * A269493 A269775 A269655 Adjacent sequences: A269686 A269687 A269688 * A269690 A269691 A269692 KEYWORD nonn AUTHOR R. H. Hardin, Mar 03 2016 STATUS approved

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Last modified May 30 08:27 EDT 2023. Contains 363050 sequences. (Running on oeis4.)