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A269642 Number of length-5 0..n arrays with no repeated value differing from the previous repeated value by other than plus two or minus 1. 1
12, 159, 796, 2637, 6876, 15307, 30444, 55641, 95212, 154551, 240252, 360229, 523836, 741987, 1027276, 1394097, 1858764, 2439631, 3157212, 4034301, 5096092, 6370299, 7887276, 9680137, 11784876, 14240487, 17089084, 20376021, 24150012 (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 + 4*n^3 + 6*n^2 - 5*n + 1.

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

G.f.: x*(12 + 87*x + 22*x^2 + 6*x^3 - 6*x^4 - x^5) / (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=3:

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

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

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

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

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

CROSSREFS

Row 5 of A269640.

Sequence in context: A015000 A220225 A213376 * A269411 A226297 A286721

Adjacent sequences:  A269639 A269640 A269641 * A269643 A269644 A269645

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 02 2016

STATUS

approved

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Last modified February 22 11:21 EST 2020. Contains 332135 sequences. (Running on oeis4.)