The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A209906 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
Showing all changes.

A209906

Half the number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two or four distinct clockwise edge differences.
(history; published version)

#9 by Bruno Berselli at Fri Jul 13 08:19:22 EDT 2018

STATUS

reviewed

approved

#8 by Michel Marcus at Fri Jul 13 08:07:30 EDT 2018

STATUS

proposed

reviewed

#7 by Colin Barker at Fri Jul 13 08:01:46 EDT 2018

STATUS

editing

proposed

#6 by Colin Barker at Fri Jul 13 08:01:24 EDT 2018

NAME

Half the number of (n+1)X2 X 2 0..3 arrays with every 2X2 2 X 2 subblock having two or four distinct clockwise edge differences.

COMMENTS

Column 1 of A209913.

FORMULA

Empirical: a(n) = 7*a(n-1) + 21*a(n-2) - 30*a(n-3) - 30*a(n-4) + 12*a(n-5) + 8*a(n-6).

Empirical g.f.: 2*x*(31 + 64*x - 114*x^2 - 114*x^3 + 46*x^4 + 32*x^5) / (1 - 7*x - 21*x^2 + 30*x^3 + 30*x^4 - 12*x^5 - 8*x^6). - Colin Barker, Jul 13 2018

EXAMPLE

Some solutions for n=4:

CROSSREFS

Cf. A209913.

AUTHOR

R. H. Hardin , Mar 15 2012

STATUS

approved

editing

#5 by Russ Cox at Sat Mar 31 12:37:30 EDT 2012

AUTHOR

_R. H. Hardin (rhhardin(AT)att.net) _ Mar 15 2012

Discussion

Sat Mar 31

12:37

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

#4 by Ron Hardin at Thu Mar 15 05:30:42 EDT 2012

STATUS

editing

approved

#3 by Ron Hardin at Thu Mar 15 05:30:38 EDT 2012

LINKS

R. H. Hardin, <a href="/A209906/b209906.txt">Table of n, a(n) for n = 1..210</a>

#2 by Ron Hardin at Thu Mar 15 05:30:11 EDT 2012

NAME

allocated for Ron HardinHalf the number of (n+1)X2 0..3 arrays with every 2X2 subblock having two or four distinct clockwise edge differences

DATA

62, 562, 5008, 44770, 399930, 3573388, 31926146, 285247762, 2548561164, 22770302450, 203442764450, 1817673135676, 16240122477074, 145098465897778, 1296391988417932, 11582701309989362, 103486422895200258

OFFSET

1,1

COMMENTS

Column 1 of A209913

FORMULA

Empirical: a(n) = 7*a(n-1) +21*a(n-2) -30*a(n-3) -30*a(n-4) +12*a(n-5) +8*a(n-6)

EXAMPLE

Some solutions for n=4

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

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

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

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

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

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin (rhhardin(AT)att.net) Mar 15 2012

STATUS

approved

editing

#1 by Ron Hardin at Thu Mar 15 05:26:36 EDT 2012

NAME

allocated for Ron Hardin

KEYWORD

allocated

STATUS

approved