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A221544 Number of 0..n arrays of length 6 with each element differing from at least one neighbor by something other than 1, starting with 0. 1
5, 54, 364, 1386, 4018, 9665, 20386, 39007, 69242, 115813, 184570, 282611, 418402, 601897, 844658, 1159975, 1562986, 2070797, 2702602, 3479803, 4426130, 5567761, 6933442, 8554607, 10465498, 12703285, 15308186, 18323587, 21796162, 25775993 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 6 of A221542.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 1*n^5 + 2*n^4 - 6*n^3 + 21*n^2 - 31*n + 23 for n>4.

Conjectures from Colin Barker, Aug 08 2018: (Start)

G.f.: x*(5 + 24*x + 115*x^2 - 88*x^3 + 157*x^4 - 153*x^5 + 87*x^6 - 34*x^7 + 8*x^8 - x^9) / (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>10.

(End)

EXAMPLE

Some solutions for n=6:

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

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

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

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

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

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

CROSSREFS

Cf. A221542.

Sequence in context: A275261 A208429 A275353 * A268882 A229298 A087125

Adjacent sequences:  A221541 A221542 A221543 * A221545 A221546 A221547

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 19 2013

STATUS

approved

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Last modified December 4 19:40 EST 2021. Contains 349526 sequences. (Running on oeis4.)