A207737 Number of n X 4 0..1 arrays avoiding 0 0 0 and 0 1 0 horizontally and 0 0 1 and 1 0 0 vertically.

9, 81, 361, 1849, 10201, 58081, 335241, 1946025, 11323225, 65950641, 384277609, 2239466329, 13051920025, 76070604481, 443368207881, 2584130195529, 15061392571801, 87784176001041, 511643544572521, 2982076804476025

Offset

1,1

Comments

Column 4 of A207741.

Links

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

Formula

Empirical: a(n) = 8*a(n-1) -11*a(n-2) -12*a(n-3) +13*a(n-4) +4*a(n-5) -a(n-6) for n>7.

Empirical g.f.: x*(9 + 9*x - 188*x^2 - 40*x^3 + 235*x^4 + 55*x^5 - 16*x^6) / ((1 - x)*(1 + x)*(1 - 6*x + x^2)*(1 - 2*x - x^2)). - Colin Barker, Jun 25 2018

Example

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

Crossrefs

Cf. A207741.

Sequence in context: A207428 A208370 A207422 * A221963 A207742 A207719

Adjacent sequences: A207734 A207735 A207736 * A207738 A207739 A207740

Keyword

nonn

Author

R. H. Hardin, Feb 19 2012

Status

approved