A232317 Number of (1+1)X(n+1) 0..1 arrays with every element equal to some horizontal or antidiagonal neighbor, with top left element zero.

2, 5, 16, 52, 169, 549, 1784, 5797, 18837, 61210, 198899, 646313, 2100164, 6824385, 22175521, 72058322, 234150159, 760860029, 2472379204, 8033880997, 26105721877, 84829326570, 275648943179, 895708394113, 2910562681764, 9457737786265

Offset: 1

Author

R. H. Hardin, Nov 22 2013

Keywords

• nonn

Comments

Row 1 of A232316

Examples

			Some.solutions.for.n=7
..0..0..1..1..0..0..0..1....0..0..0..1..1..0..0..0....0..0..0..1..1..1..0..0
..1..1..1..1..0..1..1..1....0..0..1..1..1..0..1..1....0..0..0..0..1..1..1..1
		

Links

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

Formula

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

Empirical: G.f.: 2*x -x^2*(-5-x+x^2+3*x^3) / ( 1-3*x-x^2+2*x^4 ). - R. J. Mathar, Nov 24 2013