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A263661 Number of length n arrays of permutations of 0..n-1 with each element moved by -3 to 3 places and with no two consecutive increases or two consecutive decreases. 1
1, 2, 4, 10, 22, 40, 70, 133, 254, 482, 902, 1710, 3214, 6094, 11446, 21702, 40766, 77294, 145190, 275286, 517102, 980446, 1841686, 3491910, 6559262, 12436622, 23361158, 44293686, 83201998, 157754302, 296328310, 561850278, 1055388926 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-2) + 2*a(n-4) for n>12.

Empirical g.f.: x*(1 + x)*(1 + x + 4*x^3 + 4*x^4 + 2*x^5 - 6*x^6 - x^7 + x^8 + 2*x^9 - 2*x^10) / (1 - 3*x^2 - 2*x^4). - Colin Barker, Jan 02 2019

EXAMPLE

Some solutions for n=7:

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

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

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

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

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

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

..6....4....6....5....5....5....4....5....6....5....6....6....5....6....6....5

CROSSREFS

Column 3 of A263666.

Sequence in context: A036954 A109679 A023036 * A005306 A075898 A274313

Adjacent sequences:  A263658 A263659 A263660 * A263662 A263663 A263664

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 23 2015

STATUS

approved

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Last modified September 17 13:00 EDT 2019. Contains 327131 sequences. (Running on oeis4.)