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A245993 Number of length n+2 0..6 arrays with no pair in any consecutive three terms totalling exactly 6. 1
216, 1116, 5766, 29790, 153906, 795144, 4108062, 21223992, 109652160, 566509902, 2926831878, 15121261374, 78122885724, 403616150730, 2085253182384, 10773307330236, 55659500700198, 287560720444278, 1485661331645130 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) + a(n-2) + 25*a(n-3) + 5*a(n-4).

Empirical g.f.: 6*x*(36 + 42*x + 181*x^2 + 35*x^3) / (1 - 4*x - x^2 - 25*x^3 - 5*x^4). - Colin Barker, Nov 06 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

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

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

CROSSREFS

Column 6 of A245995.

Sequence in context: A162142 A233859 A233853 * A233980 A233974 A016863

Adjacent sequences:  A245990 A245991 A245992 * A245994 A245995 A245996

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 09 2014

STATUS

approved

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Last modified September 20 06:51 EDT 2020. Contains 337264 sequences. (Running on oeis4.)