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A246732 Number of length n+4 0..3 arrays with no pair in any consecutive five terms totalling exactly 3. 1
124, 260, 548, 1156, 2436, 5132, 10812, 22780, 47996, 101124, 213060, 448900, 945796, 1992716, 4198492, 8845884, 18637564, 39267844, 82734180, 174314244, 367266052, 773799948, 1630334076, 3434982396, 7237230844, 15248261636 (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) = 2*a(n-1) + a(n-4).

Empirical g.f.: 4*x*(31 + 3*x + 7*x^2 + 15*x^3) / (1 - 2*x - x^4). - Colin Barker, Nov 06 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

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

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

CROSSREFS

Column 3 of A246737.

Sequence in context: A045205 A045295 A045280 * A214485 A045250 A258931

Adjacent sequences:  A246729 A246730 A246731 * A246733 A246734 A246735

KEYWORD

nonn

AUTHOR

R. H. Hardin, Sep 02 2014

STATUS

approved

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Last modified October 23 17:37 EDT 2021. Contains 348215 sequences. (Running on oeis4.)