A269007 - OEIS

A269007

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

5, 36, 305, 2136, 14240, 91048, 566656, 3456320, 20760192, 123186784, 723791744, 4218132480, 24414483712, 140486492800, 804321836032, 4584741088256, 26032741150720, 147311358346752, 831044097026048, 4675403505475584

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 12*a(n-1) - 40*a(n-2) + 8*a(n-3) + 92*a(n-4) - 32*a(n-5) - 64*a(n-6) for n>7.

Empirical g.f.: x*(5 - 24*x + 73*x^2 - 124*x^3 + 60*x^4 + 16*x^5 + 4*x^6) / (1 - 6*x + 2*x^2 + 8*x^3)^2. - Colin Barker, Jan 18 2019

EXAMPLE

Some solutions for n=4:

..0..0..1..0. .1..0..1..0. .0..0..1..0. .0..1..0..0. .0..0..0..0

..0..0..0..1. .1..0..0..0. .0..1..0..0. .0..1..0..1. .0..1..0..0

..0..0..0..1. .0..1..0..1. .0..0..0..0. .1..0..0..0. .0..0..1..0

..0..1..0..1. .0..0..0..0. .1..0..0..1. .0..0..0..1. .1..0..1..0

CROSSREFS

Column 4 of A269011.

Sequence in context: A091161 A364765 A135149 * A246510 A365754 A341961

Adjacent sequences: A269004 A269005 A269006 * A269008 A269009 A269010

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 17 2016

STATUS

approved