A205313 Number of (n+1) X 4 0..1 arrays with every 2 X 2 subblock having the same number of equal edges, and new values 0..1 introduced in row major order.

56, 376, 2606, 18152, 126536, 882182, 6150512, 42881096, 298965278, 2084374136, 14532174632, 101317751318, 706383387200, 4924877262824, 34336051065326, 239389600968776, 1669014906316040, 11636306448704678, 81127872049414160

Offset

1,1

Comments

Column 3 of A205318.

Links

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

Formula

Empirical: a(n) = 10*a(n-1) -24*a(n-2) +21*a(n-3) -6*a(n-4).

Empirical g.f.: 2*x*(2 - 3*x)*(14 - 25*x + 10*x^2) / ((1 - x)*(1 - 9*x + 15*x^2 - 6*x^3)). - Colin Barker, Jun 11 2018

Example

Some solutions for n=4:
..0..1..0..1....0..1..1..0....0..0..0..0....0..0..1..1....0..0..1..0
..1..1..1..1....1..1..0..0....0..1..1..0....0..1..1..0....0..1..1..1
..0..1..0..0....0..0..0..1....1..1..0..0....0..0..0..0....1..1..0..0
..0..0..0..1....0..1..1..1....1..0..0..1....0..1..1..0....1..0..0..1
..1..1..1..1....0..1..0..0....1..1..0..1....1..1..0..0....0..0..1..1

Crossrefs

Cf. A205318.

Sequence in context: A181705 A219826 A075283 * A287702 A008447 A076647

Adjacent sequences: A205310 A205311 A205312 * A205314 A205315 A205316

Keyword

nonn

Author

R. H. Hardin, Jan 25 2012

Status

approved