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A269608 Number of length-5 0..n arrays with no repeated value differing from the previous repeated value by one or less. 1
10, 154, 804, 2692, 7030, 15630, 31024, 56584, 96642, 156610, 243100, 364044, 528814, 748342, 1035240, 1403920, 1870714, 2453994, 3174292, 4054420, 5119590, 6397534, 7918624, 9715992, 11825650, 14286610, 17141004, 20434204, 24214942 (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) = n^5 + 5*n^4 + 7*n^3 - 4*n^2 + n.

Conjectures from Colin Barker, Jan 25 2019: (Start)

G.f.: 2*x*(5 + 47*x + 15*x^2 - 11*x^3 + 4*x^4) / (1 - x)^6.

a(n) = 6*a(n-1) - 15*a(n-2) + 20*a(n-3) - 15*a(n-4) + 6*a(n-5) - a(n-6) for n>6.

(End)

EXAMPLE

Some solutions for n=7:

..2. .3. .4. .7. .7. .4. .6. .7. .1. .2. .6. .4. .1. .2. .4. .5

..6. .2. .7. .5. .3. .3. .4. .7. .4. .1. .0. .6. .5. .4. .2. .6

..1. .5. .1. .4. .6. .1. .5. .5. .2. .0. .7. .4. .3. .0. .0. .1

..4. .0. .7. .2. .4. .4. .4. .1. .7. .6. .1. .4. .6. .4. .4. .7

..7. .3. .5. .5. .4. .7. .3. .3. .2. .2. .1. .2. .6. .1. .2. .0

CROSSREFS

Row 5 of A269606.

Sequence in context: A251730 A222487 A307352 * A240196 A048907 A061654

Adjacent sequences:  A269605 A269606 A269607 * A269609 A269610 A269611

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2016

STATUS

approved

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Last modified June 17 22:14 EDT 2021. Contains 345086 sequences. (Running on oeis4.)