A188516 Number of nX2 binary arrays without the pattern 1 1 0 diagonally, vertically or horizontally

4, 16, 49, 144, 400, 1089, 2916, 7744, 20449, 53824, 141376, 370881, 972196, 2547216, 6671889, 17472400, 45751696, 119793025, 313644100, 821166336, 2149898689, 5628600576, 14736017664, 38579637889, 101003196100, 264430435984

Offset

1,1

Comments

Column 2 of A188523

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n)=4*a(n-1)-2*a(n-2)-6*a(n-3)+4*a(n-4)+2*a(n-5)-a(n-6).

Conjecture: a(n) = (F(n+3) - 1)^2, where F = A000045 (Fibonacci numbers). - Clark Kimberling, Jun 21 2016

Assuming the conjecture, define b(1) = 1 and b(n) = a(n-1) for n > 1. Then b(n) = Sum{F(i,j): (i=n and 1<=j<=n) or (j=n and 1<=i<=n)}, where F is the Fibonacci fusion array, A202453. - Clark Kimberling, Jun 21 2016

G.f. for (b(n)): -x*(-1+x^3-2*x^2) / ( (x-1)*(1+x)*(x^2-3*x+1)*(x^2+x-1) ). - R. J. Mathar, Dec 20 2011

b(n) = -2*(-1)^n/5 - 2*Fibonacci(n+2) + Lucas(2*n+4)/5 + 1. - Ehren Metcalfe, Mar 26 2016

Example

Some solutions for 3X2
..0..1....0..1....0..0....0..0....1..0....0..1....1..0....0..1....0..0....0..1
..0..0....0..0....0..0....0..1....1..1....1..0....0..1....0..1....1..0....1..0
..1..1....0..0....0..1....1..0....1..1....0..0....1..0....1..1....0..0....0..1

Crossrefs

Sequence in context: A227266 A114185 A378673 * A188501 A283692 A173712

Adjacent sequences: A188513 A188514 A188515 * A188517 A188518 A188519

Keyword

nonn

Author

R. H. Hardin, Apr 02 2011

Status

approved