The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A221737

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Number of 2 X n arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out left turns.
(history; published version)

#8 by Bruno Berselli at Fri Aug 10 17:33:47 EDT 2018

STATUS

reviewed

approved

#7 by Michel Marcus at Fri Aug 10 11:57:52 EDT 2018

STATUS

proposed

reviewed

#6 by Colin Barker at Fri Aug 10 10:26:28 EDT 2018

STATUS

editing

proposed

#5 by Colin Barker at Fri Aug 10 10:25:48 EDT 2018

NAME

Number of 2Xn 2 X n arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out left turns.

COMMENTS

Row 2 of A221736.

FORMULA

Empirical: a(n) = 15*a(n-1) - 67*a(n-2) + 120*a(n-3) - 80*a(n-4) + 10*a(n-5) for n>6.

Empirical g.f.: x*(1 + 2*x - 36*x^2 + 86*x^3 - 64*x^4 + 12*x^5) / (1 - 15*x + 67*x^2 - 120*x^3 + 80*x^4 - 10*x^5). - Colin Barker, Aug 10 2018

EXAMPLE

Some solutions for n=3:

CROSSREFS

Cf. A221736.

AUTHOR

R. H. Hardin , Jan 22 2013

STATUS

approved

editing

#4 by R. H. Hardin at Tue Jan 22 20:03:29 EST 2013

STATUS

editing

approved

#3 by R. H. Hardin at Tue Jan 22 20:03:26 EST 2013

LINKS

R. H. Hardin, <a href="/A221737/b221737.txt">Table of n, a(n) for n = 1..210</a>

#2 by R. H. Hardin at Tue Jan 22 20:03:11 EST 2013

NAME

allocated for R. H. Hardin

Number of 2Xn arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, without move-in move-out left turns

DATA

1, 17, 152, 1347, 11917, 105408, 932331, 8246429, 72939328, 645145427, 5706285509, 50471867376, 446421650827, 3948581668413, 34925047119456, 308910646572419, 2732302328399893, 24167104943016272, 213757077778269179

OFFSET

1,2

COMMENTS

Row 2 of A221736

FORMULA

Empirical: a(n) = 15*a(n-1) -67*a(n-2) +120*a(n-3) -80*a(n-4) +10*a(n-5) for n>6

EXAMPLE

Some solutions for n=3

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

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

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin Jan 22 2013

STATUS

approved

editing

#1 by R. H. Hardin at Tue Jan 22 19:57:55 EST 2013

NAME

allocated for R. H. Hardin

KEYWORD

allocated

STATUS

approved