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A269623 Number of length-7 0..n arrays with no repeated value differing from the previous repeated value by other than plus two, zero or minus 1. 1
92, 1740, 13544, 66925, 246798, 742487, 1923796, 4447329, 9398090, 18471403, 34200192, 60232661, 101665414, 165437055, 260787308, 399786697, 597941826, 874881299, 1255127320, 1768958013, 2453365502, 3353114791, 4521908484 (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 + 11*n^5 + 35*n^4 + 18*n^3 + 36*n^2 - 19*n - 7 for n>2.

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

G.f.: x*(92 + 1004*x + 2200*x^2 + 2141*x^3 - 370*x^4 + 187*x^5 - 340*x^6 + 179*x^7 - 62*x^8 + 9*x^9) / (1 - x)^8. - Colin Barker, Jan 25 2019

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>10.

(End)

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

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

CROSSREFS

Row 7 of A269619.

Sequence in context: A179798 A232795 A269439 * A265923 A249236 A166824

Adjacent sequences:  A269620 A269621 A269622 * A269624 A269625 A269626

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2016

STATUS

approved

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Last modified October 27 21:54 EDT 2021. Contains 348290 sequences. (Running on oeis4.)