login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A268991 Number of n X 4 binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once. 1

%I

%S 13,103,805,6009,43512,308112,2144780,14730784,100087792,674045392,

%T 4505925696,29933341056,197782652096,1300744853760,8519586895104,

%U 55600022810880,361688403251200,2346083095244800,15178387509332992

%N Number of n X 4 binary arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.

%H R. H. Hardin, <a href="/A268991/b268991.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 16*a(n-1) - 88*a(n-2) + 200*a(n-3) - 208*a(n-4) + 96*a(n-5) - 16*a(n-6) for n>7.

%F Empirical g.f.: x*(13 - 105*x + 301*x^2 - 407*x^3 + 312*x^4 - 112*x^5 + 4*x^6) / (1 - 8*x + 12*x^2 - 4*x^3)^2. - _Colin Barker_, Jan 17 2019

%e Some solutions for n=4:

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

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

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

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

%Y Column 4 of A268995.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 17 2016

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 25 01:40 EDT 2021. Contains 348233 sequences. (Running on oeis4.)