A207455 Number of 4 X n 0..1 arrays avoiding 0 0 0 and 0 0 1 horizontally and 0 0 1 and 1 0 1 vertically.

8, 64, 168, 760, 2560, 10088, 36456, 138176, 509960, 1910296, 7096320, 26485576, 98590024, 367542080, 1369032168, 5101852856, 19007490560, 70825236904, 263884411560, 983242576576, 3663494987848, 13650146856152, 50859864760320

Offset: 1

Author

R. H. Hardin, Feb 17 2012

Keywords

• nonn

Comments

Row 4 of A207453.

Examples

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

Links

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

Crossrefs

Cf. A207453.

Formula

Empirical: a(n) = a(n-1) + 10*a(n-2) + 3*a(n-3) - 9*a(n-4).

Empirical g.f.: 8*x*(1 + 7*x + 3*x^2 - 9*x^3) / (1 - x - 10*x^2 - 3*x^3 + 9*x^4). - Colin Barker, Jun 23 2018