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A269587 Number of length-7 0..n arrays with no repeated value differing from the previous repeated value by more than one. 1
128, 1889, 13946, 67763, 248324, 745013, 1927694, 4453031, 9406088, 18482249, 34214498, 60251099, 101688716, 165466013, 260822774, 399829583, 597993104, 874942001, 1255198538, 1769040899, 2453461268, 3353224709, 4522033886 (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 + 28*n^3 + 42*n^2 + 5*n - 1.

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

G.f.: x*(128 + 865*x + 2418*x^2 + 1919*x^3 - 116*x^4 - 129*x^5 - 46*x^6 + 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=4:

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

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

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

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

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

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

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

CROSSREFS

Row 7 of A269583.

Sequence in context: A269081 A200789 A250356 * A232053 A250234 A093528

Adjacent sequences:  A269584 A269585 A269586 * A269588 A269589 A269590

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2016

STATUS

approved

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Last modified September 21 23:55 EDT 2019. Contains 327286 sequences. (Running on oeis4.)