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 A269686 Number of length-n 0..4 arrays with no repeated value differing from the previous repeated value by plus or minus one modulo 4+1. 1
 5, 25, 125, 615, 2995, 14465, 69405, 331255, 1574195, 7454385, 35195485, 165766535, 779138355, 3655796065, 17128371485, 80151962775, 374677320115, 1749902587025, 8166591981405, 38087874378535, 177538468225715, 827166275107905 (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) = 8*a(n-1) - 13*a(n-2) - 12*a(n-3). Conjectures from Colin Barker, Jan 27 2019: (Start) G.f.: 5*x*(1 - 3*x - 2*x^2) / ((1 - 4*x)*(1 - 4*x - 3*x^2)). a(n) = (-5/42)*(7*4^n + (2-sqrt(7))^n*(-7+3*sqrt(7)) - (2+sqrt(7))^n*(7+3*sqrt(7))). (End) EXAMPLE Some solutions for n=7: ..3. .0. .4. .1. .2. .2. .2. .3. .2. .3. .3. .0. .0. .2. .2. .3 ..1. .3. .2. .3. .4. .0. .3. .0. .2. .1. .4. .0. .2. .2. .0. .3 ..2. .0. .3. .0. .0. .1. .1. .2. .2. .0. .1. .4. .2. .2. .3. .4 ..2. .4. .2. .2. .3. .1. .1. .1. .2. .0. .0. .1. .2. .3. .0. .2 ..2. .3. .3. .1. .0. .0. .1. .3. .4. .0. .0. .0. .4. .4. .3. .3 ..2. .3. .2. .4. .2. .1. .3. .2. .2. .2. .2. .2. .3. .0. .2. .2 ..1. .3. .3. .0. .3. .2. .4. .4. .1. .3. .4. .4. .1. .4. .0. .4 CROSSREFS Column 4 of A269690. Sequence in context: A269615 A269579 A269431 * A269490 A269772 A269652 Adjacent sequences: A269683 A269684 A269685 * A269687 A269688 A269689 KEYWORD nonn AUTHOR R. H. Hardin, Mar 03 2016 STATUS approved

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Last modified December 7 04:56 EST 2023. Contains 367629 sequences. (Running on oeis4.)