The On-Line Encyclopedia of Integer Sequences (OEIS)

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A248428

Number of length n+2 0..3 arrays with every three consecutive terms having the sum of some two elements equal to twice the third.
(history; published version)

#8 by Bruno Berselli at Thu Nov 08 06:34:18 EST 2018

STATUS

proposed

approved

#7 by Colin Barker at Thu Nov 08 06:26:29 EST 2018

STATUS

editing

proposed

#6 by Colin Barker at Thu Nov 08 06:26:11 EST 2018

NAME

Number of length n+2 0..3 arrays with every three consecutive terms having the sum of some two elements equal to twice the third.

COMMENTS

Column 3 of A248433

FORMULA

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

Empirical g.f.: 4*x*(4 + x + x^2 - 7*x^3) / ((1 - x)*(1 - 2*x^3)). - Colin Barker, Nov 08 2018

EXAMPLE

Some solutions for n=6:

CROSSREFS

Column 3 of A248433.

STATUS

approved

editing

#5 by R. H. Hardin at Mon Oct 06 16:30:56 EDT 2014

STATUS

editing

approved

#4 by R. H. Hardin at Mon Oct 06 16:30:52 EDT 2014

LINKS

R. H. Hardin, <a href="/A248428/b248428.txt">Table of n, a(n) for n = 1..210</a>

#3 by R. H. Hardin at Mon Oct 06 16:30:30 EDT 2014

NAME

allocated for R. H. Hardin

Number of length n+2 0..3 arrays with every three consecutive terms having the sum of some two elements equal to twice the third

DATA

16, 20, 24, 28, 36, 44, 52, 68, 84, 100, 132, 164, 196, 260, 324, 388, 516, 644, 772, 1028, 1284, 1540, 2052, 2564, 3076, 4100, 5124, 6148, 8196, 10244, 12292, 16388, 20484, 24580, 32772, 40964, 49156, 65540, 81924, 98308, 131076, 163844, 196612, 262148

OFFSET

1,1

COMMENTS

Column 3 of A248433

FORMULA

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

EXAMPLE

Some solutions for n=6

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

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

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

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

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

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

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

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

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin, Oct 06 2014

STATUS

approved

editing

#2 by R. H. Hardin at Mon Oct 06 16:28:43 EDT 2014

KEYWORD

allocating

allocated

#1 by R. H. Hardin at Mon Oct 06 16:28:43 EDT 2014

NAME

allocated for R. H. Hardin

KEYWORD

allocating

STATUS

approved