login
A283410
Number of n X 3 0..1 arrays with no 1 equal to more than three of its horizontal, vertical and antidiagonal neighbors.
1
8, 61, 416, 2944, 20744, 146228, 1030788, 7266120, 51219756, 361053936, 2545110952, 17940781184, 126466639652, 891477956620, 6284131129240, 44297566481868, 312258664857680, 2201147411081008, 15516142450416040
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 5*a(n-1) + 13*a(n-2) + 10*a(n-3) + a(n-4) + 2*a(n-5) for n>7.
Empirical g.f.: x*(1 + x)*(8 + 13*x - 6*x^2 - 3*x^3 + x^4 - 2*x^5) / (1 - 5*x - 13*x^2 - 10*x^3 - x^4 - 2*x^5). - Colin Barker, Feb 21 2019
EXAMPLE
Some solutions for n=4:
..0..0..1. .1..0..0. .1..0..1. .1..0..0. .1..0..1. .0..0..0. .0..1..1
..0..0..1. .0..0..1. .0..1..0. .1..0..0. .1..1..0. .0..1..0. .0..0..1
..1..1..0. .0..0..0. .0..1..0. .0..0..0. .0..0..0. .1..0..0. .1..1..0
..1..0..1. .0..0..1. .0..1..1. .1..1..0. .0..0..1. .0..1..0. .0..1..1
CROSSREFS
Column 3 of A283415.
Sequence in context: A071401 A247535 A283852 * A081907 A278596 A190976
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 07 2017
STATUS
approved