The OEIS is supported by the many generous donors to the OEIS Foundation.

Number of (n+1) X 2 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor.
3

%I #8 Feb 23 2018 09:51:41

%S 81,360,1683,7572,35577,160218,750426,3387924,15834846,71633088,

%T 334163931,1514409882,7052640282,32013216726,148862055267,

%U 676669161648,3142331422251,14301747527646,66336358731993,302253567013566

%N Number of (n+1) X 2 0..2 arrays with the number of clockwise edge increases in every 2 X 2 subblock differing from each horizontal or vertical neighbor.

%C Column 1 of A205520.

%H R. H. Hardin, <a href="/A205513/b205513.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 18*a(n-2) +6*a(n-3) +39*a(n-4) -2*a(n-5) -3*a(n-6) -4*a(n-7).

%F Empirical g.f.: 3*x*(27 + 120*x + 75*x^2 + 202*x^3 - 12*x^4 - 18*x^5 - 22*x^6) / (1 - 18*x^2 - 6*x^3 - 39*x^4 + 2*x^5 + 3*x^6 + 4*x^7). - _Colin Barker_, Feb 23 2018

%e Some solutions for n=4:

%e ..1..1....0..1....2..1....2..2....2..1....2..0....1..2....0..0....2..1....2..1

%e ..1..0....2..1....2..2....2..0....2..2....2..2....2..2....2..1....0..2....1..2

%e ..2..1....2..2....1..0....2..1....2..2....2..2....1..0....0..1....1..2....1..1

%e ..2..0....1..0....0..0....0..1....2..1....0..2....1..0....2..0....1..0....1..1

%e ..1..2....2..2....2..1....2..0....1..2....1..0....2..1....2..0....2..2....1..2

%Y Cf. A205520.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jan 28 2012

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified September 20 14:16 EDT 2024. Contains 376072 sequences. (Running on oeis4.)