|
|
A281202
|
|
Number of n X 5 0..1 arrays with no element equal to more than one of its horizontal and antidiagonal neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
|
|
1
|
|
|
5, 52, 176, 470, 1141, 2602, 5712, 12208, 25577, 52784, 107636, 217370, 435473, 866550, 1714460, 3375236, 6616061, 12919308, 25142632, 48783294, 94395997, 182209890, 350933080, 674521464, 1294078657, 2478473672, 4739410828
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
FORMULA
|
Empirical: a(n) = 4*a(n-1) - 4*a(n-2) - 2*a(n-4) + 4*a(n-5) - a(n-8).
Empirical g.f.: x*(5 + 32*x - 12*x^2 - 26*x^3 - 25*x^4 + 2*x^5 + 12*x^6 + 4*x^7) / ((1 - x)^2*(1 - x - x^2 - x^3)^2). - Colin Barker, Feb 17 2019
|
|
EXAMPLE
|
Some solutions for n=4:
..0..1..0..1..0. .0..1..1..0..1. .0..1..0..0..1. .0..1..1..0..1
..0..0..0..1..0. .0..0..1..0..1. .1..0..1..0..1. .0..1..0..1..0
..0..1..0..1..0. .1..1..1..0..1. .1..0..1..0..1. .0..1..0..1..1
..1..0..1..0..1. .1..0..1..0..0. .0..1..0..1..0. .0..1..0..0..1
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|