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A269413 Number of length-7 0..n arrays with no repeated value greater than or equal to the previous repeated value. 1
20, 957, 10132, 56890, 223320, 695135, 1837752, 4302612, 9168780, 18124865, 33696300, 59523022, 100692592, 164133795, 259075760, 397577640, 595133892, 871360197, 1250765060, 1763612130, 2446878280, 3345312487, 4512600552 (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 + (8/3)*n^4 - (11/6)*n^3 + (1/3)*n^2 - (1/6)*n.

Conjectures from Colin Barker, Jan 21 2019: (Start)

G.f.: x*(20 + 797*x + 3036*x^2 + 1510*x^3 - 296*x^4 - 27*x^5) / (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:

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

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

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

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

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

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

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

CROSSREFS

Row 7 of A269409.

Sequence in context: A066802 A066798 A072035 * A274764 A069578 A269644

Adjacent sequences:  A269410 A269411 A269412 * A269414 A269415 A269416

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 25 2016

STATUS

approved

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Last modified November 26 21:07 EST 2021. Contains 349344 sequences. (Running on oeis4.)