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A269541 Number of length-7 0..n arrays with no repeated value differing from the previous repeated value by other than one. 1
30, 1048, 10192, 55836, 217714, 677200, 1792788, 4205812, 8981446, 17790024, 33133720, 58623628, 99312282, 162086656, 256126684, 393434340, 589438318, 863679352, 1240581216, 1750312444, 2429743810, 3323506608, 4485156772 (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^7 + 7*n^6 + 6*n^5 + 20*n^4 - 12*n^3 + 22*n^2 - 18*n + 4.

Conjectures from Colin Barker, Jan 24 2019: (Start)

G.f.: 2*x*(15 + 404*x + 1324*x^2 + 982*x^3 - 93*x^4 - 88*x^5 - 22*x^6 - 2*x^7) / (1 - x)^8.

a(n) = 8*a(n-1) - 28*a(n-2) + 56*a(n-3) - 70*a(n-4) + 56*a(n-5) - 28*a(n-6) + 8*a(n-7) - a(n-8) for n>8.

(End)

EXAMPLE

Some solutions for n=3:

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

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

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

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

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

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

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

CROSSREFS

Row 7 of A269537.

Sequence in context: A160313 A001821 A027488 * A280216 A075187 A265101

Adjacent sequences:  A269538 A269539 A269540 * A269542 A269543 A269544

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 29 2016

STATUS

approved

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Last modified December 7 04:21 EST 2021. Contains 349567 sequences. (Running on oeis4.)