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A221543 Number of 0..n arrays of length 5 with each element differing from at least one neighbor by something other than 1, starting with 0. 1
3, 22, 103, 303, 716, 1455, 2658, 4487, 7128, 10791, 15710, 22143, 30372, 40703, 53466, 69015, 87728, 110007, 136278, 166991, 202620, 243663, 290642, 344103, 404616, 472775, 549198, 634527, 729428, 834591, 950730, 1078583, 1218912 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 5 of A221542.

LINKS

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

FORMULA

Empirical: a(n) = 1*n^4 + 1*n^3 - 3*n^2 + 10*n - 9 for n>3.

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

G.f.: x*(3 + 7*x + 23*x^2 - 22*x^3 + 26*x^4 - 18*x^5 + 6*x^6 - x^7) / (1 - x)^5.

a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>8.

(End)

EXAMPLE

Some solutions for n=6:

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

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

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

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

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

CROSSREFS

Cf. A221542.

Sequence in context: A254332 A009029 A009032 * A309000 A061182 A143552

Adjacent sequences:  A221540 A221541 A221542 * A221544 A221545 A221546

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 19 2013

STATUS

approved

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Last modified September 21 09:44 EDT 2020. Contains 337268 sequences. (Running on oeis4.)