A207458 Number of 7 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 1 vertically.

14, 196, 546, 3850, 14896, 84266, 370734, 1922564, 8935850, 44655394, 212625504, 1045480786, 5031607126, 24563900900, 118782802866, 578049254426, 2801168057744, 13612500276634, 66026807997150, 320661548440324

Offset: 1

Author

R. H. Hardin, Feb 17 2012

Keywords

• nonn

Comments

Row 7 of A207453.

Examples

			Some solutions for n=5:
  0 1 0 1 0     1 0 1 1 0     1 1 0 1 0     1 1 0 1 1
  0 1 1 1 0     0 1 0 1 0     0 1 0 1 1     1 0 1 0 1
  0 1 0 1 0     0 1 0 1 0     0 1 0 1 1     1 0 1 0 1
  0 1 0 1 0     0 1 0 1 0     0 1 0 1 1     1 0 1 0 0
  0 1 0 1 0     0 1 0 1 0     0 1 0 1 1     1 0 1 0 0
  0 1 0 1 0     0 1 0 1 0     0 1 0 1 1     1 0 1 0 0
  0 1 0 1 0     0 1 0 1 0     0 1 0 1 1     1 0 1 0 0
		

Links

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

Crossrefs

Cf. A207453.

Formula

Empirical: a(n) = a(n-1) + 19*a(n-2) + 6*a(n-3) - 36*a(n-4).

Empirical g.f.: 14*x*(1 + 13*x + 6*x^2 - 36*x^3) / ((1 + 2*x - 4*x^2)*(1 - 3*x - 9*x^2)). - Colin Barker, Jun 23 2018