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!)
A269031 Number of n X 4 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once. 1

%I

%S 36,216,2166,18384,146064,1114848,8277072,60218112,431354928,

%T 3052215072,21383561232,148585984320,1025363155440,7034327057760,

%U 48013557090768,326276117933952,2208609401649072,14899002865010592,100198549907000208

%N Number of n X 4 0..2 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling two exactly once.

%H R. H. Hardin, <a href="/A269031/b269031.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 14*a(n-1) - 57*a(n-2) + 56*a(n-3) - 16*a(n-4) for n>5.

%F Empirical g.f.: 6*x*(6 - 48*x + 199*x^2 - 274*x^3 + 105*x^4) / (1 - 7*x + 4*x^2)^2. - _Colin Barker_, Jan 18 2019

%e Some solutions for n=4:

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

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

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

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

%Y Column 4 of A269035.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 18 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 May 26 18:08 EDT 2020. Contains 334630 sequences. (Running on oeis4.)