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A269610 Number of length-7 0..n arrays with no repeated value differing from the previous repeated value by one or less. 1
14, 902, 10192, 58280, 229754, 714874, 1886252, 4405772, 9366790, 18476654, 34284584, 60459952, 102126002, 166254050, 262123204, 401850644, 600997502, 879255382, 1261218560, 1777246904, 2464424554, 3367619402, 4540648412 (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 + 16*n^5 - 12*n^4 - 5*n^3 + 18*n^2 - 15*n + 4.

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

G.f.: 2*x*(7 + 395*x + 1684*x^2 + 608*x^3 - 321*x^4 + 143*x^5 + 6*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=4:

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

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

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

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

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

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

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

CROSSREFS

Row 7 of A269606.

Sequence in context: A064345 A269335 A159871 * A115458 A241801 A199651

Adjacent sequences:  A269607 A269608 A269609 * A269611 A269612 A269613

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 01 2016

STATUS

approved

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Last modified July 18 07:10 EDT 2019. Contains 325134 sequences. (Running on oeis4.)