A207027 - OEIS

A207027

Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 1 0 1 vertically

8, 64, 168, 558, 1586, 3726, 9450, 21318, 47518, 104470, 220531, 464202, 957412, 1949906, 3940218, 7868976, 15610980, 30742563, 60142488, 117047084, 226575095, 436635184, 837955970, 1601924662, 3051891570, 5795441060, 10972726928

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Row 4 of A207024

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) -11*a(n-3) -13*a(n-4) +39*a(n-5) +29*a(n-6) -35*a(n-7) -84*a(n-8) +25*a(n-9) +53*a(n-10) +48*a(n-11) -15*a(n-12) +6*a(n-13) -69*a(n-14) -25*a(n-15) +a(n-16) +54*a(n-17) +2*a(n-18) +16*a(n-19) -12*a(n-20) -6*a(n-21) -15*a(n-22) +6*a(n-23) +3*a(n-25) +a(n-27) -a(n-28)

EXAMPLE

Some solutions for n=4

..1..0..1..0....1..0..1..0....1..1..0..1....1..0..1..0....0..0..1..0

..1..0..1..0....0..0..1..0....1..0..0..1....0..1..0..0....0..0..1..0

CROSSREFS

Sequence in context: A044195 A153808 A207601 * A207172 A207455 A207307

Adjacent sequences: A207024 A207025 A207026 * A207028 A207029 A207030

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 14 2012

STATUS

approved