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A250381 Number of length n+3 0..2 arrays with no four consecutive terms having the maximum of any two terms equal to the minimum of the remaining two terms. 1
42, 78, 146, 274, 514, 966, 1816, 3414, 6418, 12066, 22688, 42658, 80208, 150808, 283566, 533182, 1002538, 1885048, 3544452, 6664608, 12531430, 23562750, 44304934, 83306386, 156640636, 294530672, 553804746, 1041316906, 1957983912 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A250387.

LINKS

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

FORMULA

From Colin Barker, Aug 20 2017: (Start)

Empirical recurrence: a(n) = a(n-1) +2*a(n-2) -a(n-3) +3*a(n-4) -a(n-5) -7*a(n-6) +a(n-7) +a(n-10).

Empirical g.f.: 2*x*(21 + 18*x - 8*x^2 + 7*x^3 - 50*x^4 - 71*x^5 + 15*x^6 + 4*x^7 + 7*x^8 + 12*x^9) / (1 - x - 2*x^2 + x^3 - 3*x^4 + x^5 + 7*x^6 - x^7 - x^10).

(End)

EXAMPLE

Some solutions for n=6

..1....1....2....2....1....0....2....1....0....0....1....0....1....0....2....1

..0....2....0....0....0....0....1....2....1....2....0....2....0....1....0....0

..0....2....1....2....1....1....2....2....2....1....2....2....2....0....0....2

..2....1....2....0....0....2....0....0....0....0....0....1....0....1....1....0

..2....0....0....1....1....2....2....1....2....2....2....0....1....0....1....2

..0....2....2....0....0....1....1....2....1....2....0....2....2....1....0....1

..1....2....1....2....2....0....2....0....0....1....1....0....0....0....0....0

..2....0....2....2....0....2....1....0....2....0....2....2....0....2....1....2

..2....1....1....0....2....2....2....2....0....2....2....0....2....2....1....0

CROSSREFS

Sequence in context: A068700 A303283 A135850 * A153644 A172437 A160283

Adjacent sequences:  A250378 A250379 A250380 * A250382 A250383 A250384

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 20 2014

STATUS

approved

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Last modified August 11 00:25 EDT 2020. Contains 336403 sequences. (Running on oeis4.)