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A221465 Number of 0..n arrays of length 6 with each element unequal to at least one neighbor, starting with 0. 1
5, 88, 513, 1856, 5125, 11880, 24353, 45568, 79461, 131000, 206305, 312768, 459173, 655816, 914625, 1249280, 1675333, 2210328, 2873921, 3688000, 4676805, 5867048, 7288033, 8971776, 10953125, 13269880, 15962913, 19076288, 22657381, 26757000 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A221463.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..136

FORMULA

Empirical: a(n) = 1*n^5 + 3*n^4 + 1*n^3.

Conjectures from Colin Barker, Aug 05 2018: (Start)

G.f.: x*(5 + 58*x + 60*x^2 - 2*x^3 - x^4) / (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=6:

..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0

..4....1....4....1....2....6....5....3....4....3....6....2....2....4....5....5

..6....1....2....0....0....5....3....5....6....3....5....6....3....5....4....1

..5....3....4....0....2....3....4....0....4....2....4....2....1....0....1....6

..4....1....4....6....6....1....1....0....5....2....1....5....6....5....5....6

..2....0....3....2....1....3....3....6....0....0....0....1....1....1....2....2

CROSSREFS

Cf. A221463.

Sequence in context: A208019 A297529 A300135 * A184239 A054954 A266064

Adjacent sequences:  A221462 A221463 A221464 * A221466 A221467 A221468

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 17 2013

STATUS

approved

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Last modified August 7 15:25 EDT 2022. Contains 355989 sequences. (Running on oeis4.)