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A229015 Number of arrays of median of three adjacent elements of some length 7 0..n array, with no adjacent equal elements in the latter. 1
2, 57, 332, 1145, 3002, 6635, 13040, 23515, 39698, 63605, 97668, 144773, 208298, 292151, 400808, 539351, 713506, 929681, 1195004, 1517361, 1905434, 2368739, 2917664, 3563507, 4318514, 5195917, 6209972, 7375997, 8710410, 10230767 (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) = (19/60)*n^5 + (37/12)*n^4 + (19/12)*n^3 - (61/12)*n^2 + (31/10)*n - 1.

Conjectures from Colin Barker, Sep 13 2018: (Start)

G.f.: x*(2 + 45*x + 20*x^2 - 32*x^3 + 2*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=4:

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

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

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

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

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

CROSSREFS

Row 5 of A229012.

Sequence in context: A041391 A245783 A189057 * A324318 A058196 A024237

Adjacent sequences:  A229012 A229013 A229014 * A229016 A229017 A229018

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 10 2013

STATUS

approved

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Last modified September 23 04:52 EDT 2021. Contains 347609 sequences. (Running on oeis4.)