The On-Line Encyclopedia of Integer Sequences (OEIS)

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A195956

Number of n X 2 0..4 arrays with each element equal to the number its horizontal and vertical neighbors unequal to itself.
(history; published version)

#9 by Bruno Berselli at Tue May 08 06:20:16 EDT 2018

STATUS

reviewed

approved

#8 by Michel Marcus at Tue May 08 05:27:37 EDT 2018

STATUS

proposed

reviewed

#7 by Colin Barker at Tue May 08 05:21:26 EDT 2018

STATUS

editing

proposed

#6 by Colin Barker at Tue May 08 05:20:58 EDT 2018

NAME

Number of nX2 n X 2 0..4 arrays with each element equal to the number its horizontal and vertical neighbors unequal to itself.

COMMENTS

Column 2 of A195962.

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-3) -a(n-4) -2*a(n-6).

Empirical g.f.: x*(1 + 5*x^2 - 4*x^3 - 2*x^4 - 8*x^5) / ((1 - x)*(1 + x + x^2)*(1 - x - 2*x^3)). - Colin Barker, May 08 2018

EXAMPLE

All solutions for n=5:

CROSSREFS

Cf. A195962.

AUTHOR

R. H. Hardin , Sep 25 2011

STATUS

approved

editing

#5 by Russ Cox at Sat Mar 31 12:36:25 EDT 2012

AUTHOR

_R. H. Hardin (rhhardin(AT)att.net) _ Sep 25 2011

Discussion

Sat Mar 31

12:36

OEIS Server: https://oeis.org/edit/global/875

#4 by Ron Hardin at Sun Sep 25 20:13:39 EDT 2011

STATUS

editing

approved

#3 by Ron Hardin at Sun Sep 25 20:13:34 EDT 2011

LINKS

R. H. Hardin, <a href="/A195956/b195956.txt">Table of n, a(n) for n = 1..200</a>

#2 by Ron Hardin at Sun Sep 25 20:13:06 EDT 2011

NAME

allocated for Ron HardinNumber of nX2 0..4 arrays with each element equal to the number its horizontal and vertical neighbors unequal to itself

DATA

1, 1, 6, 5, 5, 14, 21, 29, 54, 93, 149, 254, 437, 733, 1238, 2109, 3573, 6046, 10261, 17405, 29494, 50013, 84821, 143806, 243829, 413469, 701078, 1188733, 2015669, 3417822, 5795285, 9826621, 16662262, 28252829, 47906069, 81230590, 137736245

OFFSET

1,3

COMMENTS

Column 2 of A195962

FORMULA

Empirical: a(n) = a(n-1) +3*a(n-3) -a(n-4) -2*a(n-6)

EXAMPLE

All solutions for n=5

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

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

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

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

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

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin (rhhardin(AT)att.net) Sep 25 2011

STATUS

approved

editing

#1 by Ron Hardin at Sun Sep 25 20:10:52 EDT 2011

NAME

allocated for Ron Hardin

KEYWORD

allocated

STATUS

approved