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A212825 Number of 0..4 arrays of length n with no adjacent pair equal to its immediately preceding adjacent pair, and new values introduced in 0..4 order. 1
1, 2, 5, 13, 44, 167, 695, 3070, 14074, 65958, 313098, 1497216, 7189646, 34606966, 166803484, 804596882, 3882748894, 18741593296, 90476092366, 436812623774, 2108996095916, 10182801139146, 49166003981046, 237391983175872 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 4 of A212829.

LINKS

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

FORMULA

Empirical: a(n) = 7*a(n-1) - 7*a(n-2) - 20*a(n-3) + 10*a(n-4) + 24*a(n-5) + 8*a(n-6) for n>9.

Empirical g.f.: x*(1 + x + x^2)*(1 - 6*x + 3*x^2 + 15*x^3 - 9*x^5 - 3*x^6) / ((1 - x - x^2)*(1 - 2*x - 2*x^2)*(1 - 4*x - 4*x^2)). - Colin Barker, Jul 21 2018

EXAMPLE

Some solutions for n=8:

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

..1....1....1....1....1....1....0....1....1....0....1....1....1....1....1....1

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

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

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

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

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

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

CROSSREFS

Cf. A212829.

Sequence in context: A287008 A119533 A066740 * A212826 A212827 A212828

Adjacent sequences:  A212822 A212823 A212824 * A212826 A212827 A212828

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 28 2012

STATUS

approved

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Last modified January 26 17:34 EST 2020. Contains 331280 sequences. (Running on oeis4.)