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A269602 Number of length-n 0..4 arrays with no repeated value differing from the previous repeated value by one or less. 1
5, 25, 120, 572, 2692, 12570, 58280, 268704, 1233046, 5636046, 25675580, 116635916, 528551090, 2390183046, 10789164304, 48625122028, 218845692934, 983773248134, 4417701453060, 19819733378212, 88847987191058, 398004177820814 (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) = 13*a(n-1) - 49*a(n-2) - 5*a(n-3) + 292*a(n-4) - 70*a(n-5) - 658*a(n-6) - 344*a(n-7).

Empirical g.f.: x*(5 - 40*x + 40*x^2 + 262*x^3 - 199*x^4 - 748*x^5 - 362*x^6) / ((1 - 4*x)*(1 - 9*x + 13*x^2 + 57*x^3 - 64*x^4 - 186*x^5 - 86*x^6)). - Colin Barker, Jan 24 2019

EXAMPLE

Some solutions for n=7:

..0. .1. .1. .4. .3. .2. .1. .2. .1. .2. .4. .4. .1. .3. .4. .1

..1. .0. .4. .1. .1. .1. .4. .4. .1. .3. .2. .1. .4. .4. .1. .1

..4. .0. .4. .0. .0. .0. .1. .1. .2. .0. .2. .4. .0. .3. .0. .2

..4. .4. .2. .1. .0. .1. .1. .1. .3. .3. .4. .4. .1. .2. .4. .1

..0. .4. .4. .3. .2. .0. .3. .2. .2. .1. .2. .2. .1. .2. .2. .3

..1. .2. .3. .1. .3. .3. .4. .1. .0. .0. .4. .3. .2. .0. .1. .1

..3. .4. .1. .0. .1. .4. .4. .3. .4. .3. .0. .2. .4. .3. .0. .4

CROSSREFS

Column 4 of A269606.

Sequence in context: A269533 A269405 A269674 * A089927 A269463 A068539

Adjacent sequences:  A269599 A269600 A269601 * A269603 A269604 A269605

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2016

STATUS

approved

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Last modified September 19 14:36 EDT 2020. Contains 337178 sequences. (Running on oeis4.)